WHERE Clause in GQL

<h2 id="where-clause-in-gql" class="position-relative d-flex align-items-center group"> WHERE Clause in GQL <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="where-clause-in-gql" aria-haspopup="dialog" aria-label="Share link: WHERE Clause in GQL"> Share link </button> </h2><div id="headingShareModal" class="heading-share-modal" role="dialog" aria-modal="true" aria-labelledby="headingShareTitle" hidden> <div class="hsm-dialog" role="document"> <div class="hsm-header"> <h2 id="headingShareTitle" class="h6 mb-0 fw-bold">Share this section</h2> <button type="button" class="hsm-close" aria-label="Close"> </button> </div> <div class="hsm-body"> <label for="headingShareInput" class="form-label small text-muted mb-1 text-uppercase fw-bold" style="font-size: 0.7rem; letter-spacing: 0.5px;">Permalink</label> <div class="input-group mb-4 hsm-url-group"> <input id="headingShareInput" type="text" class="form-control font-monospace" readonly aria-readonly="true" style="font-size: 0.85rem;" /> <button class="btn btn-primary hsm-copy" type="button" aria-label="Copy" title="Copy"> </button> </div> <div class="small fw-bold mb-2 text-muted text-uppercase" style="font-size: 0.7rem; 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'fa-duotone fa-clipboard-check':'fa-duotone fa-circle-exclamation'; setTimeout(()=>{ icon.className=prev; },1800); } function handleShareClick(e){ e.preventDefault(); const btn=e.currentTarget; const id=btn.getAttribute('data-share-target'); if(id) openModal(id); } function bindShareButtons(){ document.querySelectorAll('.h-share').forEach(btn=>{ if(!btn.dataset.hShareBound){ btn.addEventListener('click', handleShareClick); btn.dataset.hShareBound='1'; } }); } bindShareButtons(); if(document.readyState==='loading'){ document.addEventListener('DOMContentLoaded', bindShareButtons); } else { requestAnimationFrame(bindShareButtons); } document.addEventListener('click', function(e){ const shareBtn=e.target.closest && e.target.closest('.h-share'); if(shareBtn && !shareBtn.dataset.hShareBound){ handleShareClick.call(shareBtn, e); } }, true); document.addEventListener('click', e=>{ if(e.target===modal) closeModal(); if(e.target.closest && e.target.closest('.hsm-close')){ e.preventDefault(); closeModal(); } if(copyBtn && (e.target===copyBtn || (e.target.closest && e.target.closest('.hsm-copy')))) { e.preventDefault(); copyCurrent(); } }); document.addEventListener('keydown', e=>{ if(e.key==='Escape' && isOpen()) closeModal(); }); function trapFocus(){ if(trapBound) return; trapBound=true; modal.addEventListener('keydown', f=>{ if(f.key==='Tab' && isOpen()){ const focusable=[...modal.querySelectorAll('a[href],button,input,textarea,select,[tabindex]:not([tabindex="-1"])')].filter(el=>!el.hasAttribute('disabled')); if(!focusable.length) return; const first=focusable[0]; const last=focusable[focusable.length-1]; if(f.shiftKey && document.activeElement===first){ f.preventDefault(); last.focus(); } else if(!f.shiftKey && document.activeElement===last){ f.preventDefault(); first.focus(); } } }); } if(closeBtn) closeBtn.addEventListener('click', e=>{ e.preventDefault(); closeModal(); }); })(); </script>The WHERE clause filters graph elements based on conditions and predicates. It is one of the most frequently used clauses in GQL, allowing you to narrow down matched patterns to only those that meet specific criteria. Mastering WHERE is essential for writing efficient, precise queries. Geode implements the WHERE clause according to the ISO/IEC 39075:2024 GQL standard. <h3 id="introduction-to-where" class="position-relative d-flex align-items-center group"> Introduction to WHERE <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="introduction-to-where" aria-haspopup="dialog" aria-label="Share link: Introduction to WHERE"> Share link </button> </h3>The WHERE clause evaluates conditions against each potential result from a MATCH or other clause, including only rows where the condition evaluates to TRUE. It supports a rich set of comparison operators, boolean logic, pattern predicates, and functions. Key characteristics of WHERE: <ul> <li>Boolean Evaluation: Conditions must evaluate to TRUE for inclusion</li> <li>Short-Circuit Evaluation: AND/OR operations stop early when result is determined</li> <li>NULL Handling: NULL comparisons have special three-valued logic semantics</li> <li>Pattern Predicates: Check for existence of patterns</li> <li>Index Usage: Properly written WHERE clauses can utilize indexes</li> </ul> <h3 id="basic-comparisons" class="position-relative d-flex align-items-center group"> Basic Comparisons <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="basic-comparisons" aria-haspopup="dialog" aria-label="Share link: Basic Comparisons"> Share link </button> </h3> <h4 id="equality-and-inequality" class="position-relative d-flex align-items-center group"> Equality and Inequality <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="equality-and-inequality" aria-haspopup="dialog" aria-label="Share link: Equality and Inequality"> Share link </button> </h4>Compare values for equality. <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">-- Equality MATCH (p:Person) WHERE p.name = 'Alice' RETURN p; -- Inequality MATCH (p:Product) WHERE p.category <> 'Electronics' RETURN p.name; -- Not equal (alternative syntax) MATCH (p:Product) WHERE p.status != 'discontinued' RETURN p; </code></pre></div> <h4 id="numeric-comparisons" class="position-relative d-flex align-items-center group"> Numeric Comparisons <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="numeric-comparisons" aria-haspopup="dialog" aria-label="Share link: Numeric Comparisons"> Share link </button> </h4>Compare numeric values. <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">-- Greater than MATCH (p:Product) WHERE p.price > 100 RETURN p.name, p.price; -- Less than or equal MATCH (e:Employee) WHERE e.age <= 30 RETURN e.name; -- Range comparison MATCH (p:Product) WHERE p.price >= 50 AND p.price <= 200 RETURN p.name, p.price; -- Chained comparison MATCH (p:Product) WHERE 50 <= p.price <= 200 RETURN p.name, p.price; </code></pre></div> <h4 id="string-comparisons" class="position-relative d-flex align-items-center group"> String Comparisons <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="string-comparisons" aria-haspopup="dialog" aria-label="Share link: String Comparisons"> Share link </button> </h4>Compare string values lexicographically. <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">-- Alphabetical comparison MATCH (p:Person) WHERE p.lastName >= 'M' RETURN p.lastName; -- Case-sensitive equality MATCH (u:User) WHERE u.username = 'alice' -- Won't match 'Alice' RETURN u; -- Case-insensitive comparison MATCH (u:User) WHERE toLower(u.username) = toLower($search) RETURN u; </code></pre></div> <h3 id="boolean-logic" class="position-relative d-flex align-items-center group"> Boolean Logic <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="boolean-logic" aria-haspopup="dialog" aria-label="Share link: Boolean Logic"> Share link </button> </h3> <h4 id="and-operator" class="position-relative d-flex align-items-center group"> AND Operator <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="and-operator" aria-haspopup="dialog" aria-label="Share link: AND Operator"> Share link </button> </h4>Combine conditions that must all be true. <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">-- Simple AND MATCH (p:Product) WHERE p.price < 100 AND p.inStock = true RETURN p.name; -- Multiple AND conditions MATCH (e:Employee) WHERE e.department = 'Engineering' AND e.level >= 3 AND e.active = true RETURN e.name, e.title; </code></pre></div> <h4 id="or-operator" class="position-relative d-flex align-items-center group"> OR Operator <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="or-operator" aria-haspopup="dialog" aria-label="Share link: OR Operator"> Share link </button> </h4>Match when any condition is true. <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">-- Simple OR MATCH (p:Person) WHERE p.city = 'New York' OR p.city = 'Los Angeles' RETURN p.name, p.city; -- Multiple OR MATCH (p:Product) WHERE p.category = 'Electronics' OR p.category = 'Computers' OR p.category = 'Phones' RETURN p.name; -- Equivalent using IN MATCH (p:Product) WHERE p.category IN ['Electronics', 'Computers', 'Phones'] RETURN p.name; </code></pre></div> <h4 id="not-operator" class="position-relative d-flex align-items-center group"> NOT Operator <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="not-operator" aria-haspopup="dialog" aria-label="Share link: NOT Operator"> Share link </button> </h4>Negate conditions. <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">-- Simple NOT MATCH (p:Product) WHERE NOT p.discontinued RETURN p.name; -- NOT with complex expression MATCH (u:User) WHERE NOT (u.role = 'admin' OR u.role = 'moderator') RETURN u.name; -- NOT IN MATCH (p:Product) WHERE NOT p.category IN ['Discontinued', 'Archive'] RETURN p.name; </code></pre></div> <h4 id="complex-boolean-expressions" class="position-relative d-flex align-items-center group"> Complex Boolean Expressions <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="complex-boolean-expressions" aria-haspopup="dialog" aria-label="Share link: Complex Boolean Expressions"> Share link </button> </h4>Combine operators with parentheses. <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">-- Grouped conditions MATCH (p:Product) WHERE (p.category = 'Electronics' OR p.category = 'Computers') AND p.price < 500 AND p.rating > 4.0 RETURN p.name, p.price; -- Nested logic MATCH (e:Employee) WHERE e.active = true AND ( (e.department = 'Engineering' AND e.level >= 3) OR (e.department = 'Management' AND e.level >= 2) ) RETURN e.name, e.department, e.level; </code></pre></div> <h3 id="collection-operators" class="position-relative d-flex align-items-center group"> Collection Operators <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="collection-operators" aria-haspopup="dialog" aria-label="Share link: Collection Operators"> Share link </button> </h3> <h4 id="in-operator" class="position-relative d-flex align-items-center group"> IN Operator <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="in-operator" aria-haspopup="dialog" aria-label="Share link: IN Operator"> Share link </button> </h4>Check membership in a list. <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">-- Simple IN MATCH (p:Person) WHERE p.country IN ['USA', 'Canada', 'Mexico'] RETURN p.name, p.country; -- IN with parameter MATCH (p:Product) WHERE p.id IN $product_ids RETURN p; -- IN with property list MATCH (p:Product) WHERE 'sale' IN p.tags RETURN p.name; </code></pre></div> <h4 id="list-predicates" class="position-relative d-flex align-items-center group"> List Predicates <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="list-predicates" aria-haspopup="dialog" aria-label="Share link: List Predicates"> Share link </button> </h4>Work with list properties. <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">-- Check if list contains value MATCH (p:Post) WHERE 'technology' IN p.tags RETURN p.title; -- Check list size MATCH (p:Post) WHERE size(p.tags) > 3 RETURN p.title; -- ANY predicate MATCH (p:Product) WHERE ANY(tag IN p.tags WHERE tag STARTS WITH 'premium') RETURN p.name; -- ALL predicate MATCH (p:Product) WHERE ALL(score IN p.reviews WHERE score >= 4) RETURN p.name; -- NONE predicate MATCH (p:Product) WHERE NONE(tag IN p.tags WHERE tag = 'discontinued') RETURN p.name; </code></pre></div> <h3 id="string-predicates" class="position-relative d-flex align-items-center group"> String Predicates <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="string-predicates" aria-haspopup="dialog" aria-label="Share link: String Predicates"> Share link </button> </h3> <h4 id="starts-with" class="position-relative d-flex align-items-center group"> STARTS WITH <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="starts-with" aria-haspopup="dialog" aria-label="Share link: STARTS WITH"> Share link </button> </h4>Match string prefixes. <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">-- Simple prefix match MATCH (p:Person) WHERE p.name STARTS WITH 'Al' RETURN p.name; -- With parameter MATCH (p:Product) WHERE p.sku STARTS WITH $prefix RETURN p; -- Case-insensitive prefix MATCH (u:User) WHERE toLower(u.email) STARTS WITH 'admin' RETURN u; </code></pre></div> <h4 id="ends-with" class="position-relative d-flex align-items-center group"> ENDS WITH <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="ends-with" aria-haspopup="dialog" aria-label="Share link: ENDS WITH"> Share link </button> </h4>Match string suffixes. <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">-- Simple suffix match MATCH (u:User) WHERE u.email ENDS WITH '@company.com' RETURN u.name, u.email; -- File extension MATCH (f:File) WHERE f.name ENDS WITH '.pdf' RETURN f.name; </code></pre></div> <h4 id="contains" class="position-relative d-flex align-items-center group"> CONTAINS <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="contains" aria-haspopup="dialog" aria-label="Share link: CONTAINS"> Share link </button> </h4>Match substrings. <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">-- Simple contains MATCH (p:Product) WHERE p.description CONTAINS 'wireless' RETURN p.name; -- Search in text MATCH (a:Article) WHERE a.content CONTAINS $search_term RETURN a.title; </code></pre></div> <h4 id="regular-expressions" class="position-relative d-flex align-items-center group"> Regular Expressions <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="regular-expressions" aria-haspopup="dialog" aria-label="Share link: Regular Expressions"> Share link </button> </h4>Pattern matching with regex. <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">-- Simple regex MATCH (u:User) WHERE u.email =~ '.*@gmail\\.com$' RETURN u.email; -- Case-insensitive regex MATCH (p:Product) WHERE p.name =~ '(?i).*phone.*' RETURN p.name; -- Complex pattern MATCH (p:Person) WHERE p.phone =~ '^\\+1-[0-9]{3}-[0-9]{3}-[0-9]{4}$' RETURN p.name, p.phone; -- NOT regex MATCH (u:User) WHERE NOT u.email =~ '.*@test\\.com$' RETURN u.email; </code></pre></div> <h3 id="null-handling" class="position-relative d-flex align-items-center group"> NULL Handling <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="null-handling" aria-haspopup="dialog" aria-label="Share link: NULL Handling"> Share link </button> </h3> <h4 id="is-null" class="position-relative d-flex align-items-center group"> IS NULL <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="is-null" aria-haspopup="dialog" aria-label="Share link: IS NULL"> Share link </button> </h4>Check for missing values. <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">-- Find nodes with missing property MATCH (u:User) WHERE u.phone IS NULL RETURN u.name, u.email; -- Optional relationship check MATCH (p:Person) OPTIONAL MATCH (p)-[:EMPLOYED_BY]->(c:Company) WHERE c IS NULL RETURN p.name AS unemployed_person; </code></pre></div> <h4 id="is-not-null" class="position-relative d-flex align-items-center group"> IS NOT NULL <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="is-not-null" aria-haspopup="dialog" aria-label="Share link: IS NOT NULL"> Share link </button> </h4>Check for existing values. <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">-- Find nodes with property present MATCH (u:User) WHERE u.verified_at IS NOT NULL RETURN u.name, u.verified_at; -- Multiple null checks MATCH (p:Profile) WHERE p.bio IS NOT NULL AND p.avatar IS NOT NULL RETURN p; </code></pre></div> <h4 id="null-in-comparisons" class="position-relative d-flex align-items-center group"> NULL in Comparisons <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="null-in-comparisons" aria-haspopup="dialog" aria-label="Share link: NULL in Comparisons"> Share link </button> </h4>Understanding three-valued logic. <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">-- NULL comparisons return NULL, not FALSE MATCH (p:Product) WHERE p.discount > 0 -- Excludes NULL discounts RETURN p.name; -- Explicit NULL handling MATCH (p:Product) WHERE COALESCE(p.discount, 0) > 0 RETURN p.name; -- Handle NULL in OR MATCH (p:Product) WHERE p.discount > 0 OR p.discount IS NULL RETURN p.name; </code></pre></div> <h3 id="pattern-predicates" class="position-relative d-flex align-items-center group"> Pattern Predicates <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="pattern-predicates" aria-haspopup="dialog" aria-label="Share link: Pattern Predicates"> Share link </button> </h3> <h4 id="existence-checks" class="position-relative d-flex align-items-center group"> Existence Checks <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="existence-checks" aria-haspopup="dialog" aria-label="Share link: Existence Checks"> Share link </button> </h4>Check if patterns exist. <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">-- Has relationship MATCH (p:Person) WHERE (p)-[:WORKS_FOR]->(:Company) RETURN p.name; -- Relationship with conditions MATCH (p:Person) WHERE (p)-[:FRIEND {close: true}]->(:Person) RETURN p.name; -- No relationship exists MATCH (p:Person) WHERE NOT (p)-[:BLOCKED]->(:Person) RETURN p.name; </code></pre></div> <h4 id="pattern-with-properties" class="position-relative d-flex align-items-center group"> Pattern with Properties <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="pattern-with-properties" aria-haspopup="dialog" aria-label="Share link: Pattern with Properties"> Share link </button> </h4>Filter based on related elements. <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">-- Check related node properties MATCH (p:Person) WHERE (p)-[:LIVES_IN]->(:City {country: 'USA'}) RETURN p.name; -- Multiple pattern conditions MATCH (u:User) WHERE (u)-[:PURCHASED]->(:Product {category: 'Premium'}) AND NOT (u)-[:FLAGGED]->() RETURN u.name; </code></pre></div> <h4 id="exists-subquery" class="position-relative d-flex align-items-center group"> EXISTS Subquery <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="exists-subquery" aria-haspopup="dialog" aria-label="Share link: EXISTS Subquery"> Share link </button> </h4>Complex existence checks with subqueries. <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">-- EXISTS subquery MATCH (p:Person) WHERE EXISTS { MATCH (p)-[:AUTHORED]->(post:Post) WHERE post.views > 1000 } RETURN p.name AS popular_author; -- Negative EXISTS MATCH (c:Customer) WHERE NOT EXISTS { MATCH (c)-[:PURCHASED]->(p:Product) WHERE p.category = 'Luxury' } RETURN c.name AS non_luxury_customer; </code></pre></div> <h3 id="numeric-functions" class="position-relative d-flex align-items-center group"> Numeric Functions <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="numeric-functions" aria-haspopup="dialog" aria-label="Share link: Numeric Functions"> Share link </button> </h3> <h4 id="mathematical-comparisons" class="position-relative d-flex align-items-center group"> Mathematical Comparisons <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="mathematical-comparisons" aria-haspopup="dialog" aria-label="Share link: Mathematical Comparisons"> Share link </button> </h4>Use functions in comparisons. <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">-- Absolute value MATCH (a:Account) WHERE abs(a.balance) > 1000 RETURN a.id; -- Rounding MATCH (p:Product) WHERE round(p.price) = 100 RETURN p.name; -- Math functions MATCH (p:Point) WHERE sqrt(p.x * p.x + p.y * p.y) < 10 RETURN p; </code></pre></div> <h4 id="aggregation-in-where-via-with" class="position-relative d-flex align-items-center group"> Aggregation in WHERE (via WITH) <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="aggregation-in-where-via-with" aria-haspopup="dialog" aria-label="Share link: Aggregation in WHERE (via WITH)"> Share link </button> </h4>Filter on aggregated values. <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">-- Filter after aggregation MATCH (c:Customer)-[:PURCHASED]->(p:Product) WITH c, count(p) AS purchase_count WHERE purchase_count > 10 RETURN c.name, purchase_count; -- Multiple aggregation filters MATCH (u:User)-[:POSTED]->(post:Post) WITH u, count(post) AS posts, avg(post.likes) AS avg_likes WHERE posts >= 5 AND avg_likes > 100 RETURN u.name, posts, avg_likes; </code></pre></div> <h3 id="date-and-time-comparisons" class="position-relative d-flex align-items-center group"> Date and Time Comparisons <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="date-and-time-comparisons" aria-haspopup="dialog" aria-label="Share link: Date and Time Comparisons"> Share link </button> </h3> <h4 id="date-comparisons" class="position-relative d-flex align-items-center group"> Date Comparisons <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="date-comparisons" aria-haspopup="dialog" aria-label="Share link: Date Comparisons"> Share link </button> </h4>Filter by date values. <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">-- After date MATCH (e:Event) WHERE e.date > date('2025-01-01') RETURN e.name, e.date; -- Date range MATCH (o:Order) WHERE o.created_at >= date('2025-01-01') AND o.created_at < date('2025-02-01') RETURN o; -- Current date comparison MATCH (s:Subscription) WHERE s.expires_at < date() RETURN s AS expired_subscription; </code></pre></div> <h4 id="datetime-comparisons" class="position-relative d-flex align-items-center group"> DateTime Comparisons <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="datetime-comparisons" aria-haspopup="dialog" aria-label="Share link: DateTime Comparisons"> Share link </button> </h4>Work with timestamps. <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">-- Recent records MATCH (l:LogEntry) WHERE l.timestamp > datetime() - duration('PT1H') RETURN l; -- Time window MATCH (s:Session) WHERE s.started_at >= datetime('2025-01-15T00:00:00') AND s.started_at < datetime('2025-01-16T00:00:00') RETURN s; </code></pre></div> <h4 id="duration-calculations" class="position-relative d-flex align-items-center group"> Duration Calculations <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="duration-calculations" aria-haspopup="dialog" aria-label="Share link: Duration Calculations"> Share link </button> </h4>Filter by time differences. <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">-- Age calculation MATCH (e:Event) WHERE duration.between(e.created_at, datetime()).days > 30 RETURN e.name AS old_event; -- Activity window MATCH (u:User) WHERE u.last_login > datetime() - duration('P7D') RETURN u.name AS active_user; </code></pre></div> <h3 id="performance-optimization" class="position-relative d-flex align-items-center group"> Performance Optimization <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="performance-optimization" aria-haspopup="dialog" aria-label="Share link: Performance Optimization"> Share link </button> </h3> <h4 id="index-friendly-where-clauses" class="position-relative d-flex align-items-center group"> Index-Friendly WHERE Clauses <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="index-friendly-where-clauses" aria-haspopup="dialog" aria-label="Share link: Index-Friendly WHERE Clauses"> Share link </button> </h4>Write conditions that use indexes effectively. <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">-- Good: Equality on indexed property MATCH (u:User) WHERE u.email = $email -- Uses index RETURN u; -- Good: Prefix search on indexed property MATCH (u:User) WHERE u.email STARTS WITH 'admin' -- Uses index RETURN u; -- Less efficient: Function on indexed property MATCH (u:User) WHERE toLower(u.email) = $email -- May not use index RETURN u; </code></pre></div> <h4 id="order-of-conditions" class="position-relative d-flex align-items-center group"> Order of Conditions <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="order-of-conditions" aria-haspopup="dialog" aria-label="Share link: Order of Conditions"> Share link </button> </h4>Place most selective conditions first. <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">-- More efficient: Specific condition first MATCH (p:Product) WHERE p.sku = $sku -- Highly selective AND p.active = true -- Less selective RETURN p; -- Index hints (if supported) MATCH (p:Product) WHERE p.category = 'Electronics' USING INDEX p:Product(category) RETURN p; </code></pre></div> <h4 id="avoiding-full-scans" class="position-relative d-flex align-items-center group"> Avoiding Full Scans <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="avoiding-full-scans" aria-haspopup="dialog" aria-label="Share link: Avoiding Full Scans"> Share link </button> </h4>Write conditions that enable index usage. <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">-- Good: Uses index MATCH (p:Person {country: 'USA'}) WHERE p.age > 21 RETURN p; -- Avoid if possible: No index advantage MATCH (p:Person) WHERE p.bio CONTAINS 'engineer' -- Full text search needed RETURN p; -- Better: Use full-text index MATCH (p:Person) WHERE text_search(p.bio, 'engineer') RETURN p; </code></pre></div> <h3 id="best-practices" class="position-relative d-flex align-items-center group"> Best Practices <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="best-practices" aria-haspopup="dialog" aria-label="Share link: Best Practices"> Share link </button> </h3> <h4 id="readability" class="position-relative d-flex align-items-center group"> Readability <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="readability" aria-haspopup="dialog" aria-label="Share link: Readability"> Share link </button> </h4><ol> <li>Use Parentheses for Clarity: Make operator precedence explicit</li> </ol> <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">WHERE (a AND b) OR (c AND d) -- Clear WHERE a AND b OR c AND d -- Ambiguous to readers </code></pre></div><ol start="2"> <li>Break Complex Conditions: Use multiple lines</li> </ol> <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">WHERE p.active = true AND p.verified = true AND (p.role = 'admin' OR p.role = 'moderator') AND p.created_at > $since </code></pre></div><ol start="3"> <li>Use Meaningful Comparisons: Be explicit about intent</li> </ol> <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">-- Clear intent WHERE p.inventory > 0 -- Instead of WHERE p.inventory -- Truthy check </code></pre></div> <h4 id="common-patterns" class="position-relative d-flex align-items-center group"> Common Patterns <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="common-patterns" aria-haspopup="dialog" aria-label="Share link: Common Patterns"> Share link </button> </h4><ol> <li>Optional with Default: Handle missing values</li> </ol> <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">WHERE COALESCE(p.discount, 0) >= $min_discount </code></pre></div><ol start="2"> <li>Safe Navigation: Check existence before accessing</li> </ol> <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">WHERE p.settings IS NOT NULL AND p.settings.notifications = true </code></pre></div><ol start="3"> <li>Range Queries: Use consistent ordering</li> </ol> <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">WHERE $min <= p.price AND p.price <= $max </code></pre></div> <h4 id="avoiding-pitfalls" class="position-relative d-flex align-items-center group"> Avoiding Pitfalls <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="avoiding-pitfalls" aria-haspopup="dialog" aria-label="Share link: Avoiding Pitfalls"> Share link </button> </h4><ol> <li>NULL Awareness: Remember NULL != FALSE</li> </ol> <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">-- This excludes NULLs WHERE p.active = true -- This includes NULLs WHERE p.active = true OR p.active IS NULL </code></pre></div><ol start="2"> <li>Type Mismatches: Ensure compatible types</li> </ol> <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">-- String vs number comparison WHERE p.price > 100 -- Good WHERE p.price > '100' -- Type mismatch risk </code></pre></div><ol start="3"> <li>Case Sensitivity: Be explicit about case handling</li> </ol> <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">-- Explicit case handling WHERE toLower(u.email) = toLower($email) </code></pre></div> <h3 id="related-topics" class="position-relative d-flex align-items-center group"> Related Topics <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="related-topics" aria-haspopup="dialog" aria-label="Share link: Related Topics"> Share link </button> </h3><ul> <li><a href="/tags/match/" >MATCH Clause</a> : Pattern matching before filtering</li> <li><a href="/tags/with/" >WITH Clause</a> : Intermediate filtering</li> <li><a href="/tags/return/" >RETURN Clause</a> : Output after filtering</li> <li><a href="/tags/operators/" >Operators</a> : Comparison and logical operators</li> <li><a href="/tags/gql-reference/" >GQL Reference</a> : Complete GQL language reference</li> <li><a href="/tags/query-optimization/" >Query Optimization</a> : Performance tuning</li> <li><a href="/tags/indexing/" >Indexing</a> : Index usage for filtering</li> </ul> <h3 id="further-reading" class="position-relative d-flex align-items-center group"> Further Reading <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="further-reading" aria-haspopup="dialog" aria-label="Share link: Further Reading"> Share link </button> </h3><ul> <li>GQL Tutorial - Filtering Data: <code>/docs/gql-tutorial/filtering-data/</code></li> <li>Query Patterns Guide: <code>/docs/guides/query-patterns/</code></li> <li>Performance Optimization: <code>/docs/performance/query-optimization/</code></li> <li>Index Guide: <code>/docs/reference/indexes/</code></li> <li>Functions Reference: <code>/docs/gql-reference/functions/</code></li> </ul>

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