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Brendan Clement
d0ed4d1a7a
- CREATE INDEX: the example left out USING, which the server requires, and the page said SQL cannot choose the algorithm or name the index. USING names the algorithm, the page lists them, and a name before ON is taken where the deployment's configuration allows it. - The search join passed fts() a bare string; fts() takes JSON. - Sampling a subquery's result is refused, so the sampling and subquery pages sample the table inside the subquery, and the refusals list it. - Two unaliased casts in one projection produce the same column name; the example aliases them. - A json_get nested in another json_get is refused. The page shows one level of nesting and json_extract with a JSONPath for deeper values, and corrects what json_extract and json_extract_with_type return.
85 lines
2.9 KiB
Plaintext
85 lines
2.9 KiB
Plaintext
---
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title: "Operators and literals"
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sidebarTitle: "Operators"
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description: "Comparison, logical and arithmetic operators, literals, and precedence."
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icon: plus-minus
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keywords: ["operators", "literals", "precedence", "null", "cast", "interval"]
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---
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<Badge color="red">Enterprise</Badge> [SQL runs on a deployment.](/sql)
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The operator set is DataFusion's. This page covers what is worth knowing when
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the operands are Lance columns.
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## Comparison {#comparison}
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| --- | --- |
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| `=` `!=` `<>` `<` `<=` `>` `>=` | ordinary comparison |
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| `IS NULL` / `IS NOT NULL` | null test — `= NULL` is never true |
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| `IS DISTINCT FROM` | comparison that treats null as a value |
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| `BETWEEN a AND b` | inclusive range |
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| `IN (...)` | set membership |
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| `LIKE` / `ILIKE` | pattern match, `%` and `_` |
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| `~` `~*` `!~` | regular expression match |
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<Note>
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For keyword matching on a text column, [`contains_tokens`](/sql/scalar-functions#contains-tokens)
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is index-accelerated where `LIKE` is not. Reach for `LIKE` only when you need
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its wildcard semantics.
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</Note>
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## Logical {#logical}
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`AND`, `OR`, `NOT`. Three-valued: a comparison against null is **unknown**, and
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`NOT unknown` is still unknown. A `WHERE` clause keeps only rows where the
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predicate is true, so unknown behaves like false there — but not inside `NOT
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IN`, which is the usual place this bites. See
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[Subqueries](/sql/dql/subqueries#in-exists).
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## Arithmetic {#arithmetic}
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`+` `-` `*` `/` `%`, with the usual precedence. String concatenation is `||`.
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<Warning>
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Arithmetic over a vector column is **list** arithmetic, not scalar arithmetic —
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a vector is a `FixedSizeList<Float32>`. When the operation you want is a
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similarity comparison, use [vector search](/search/vector-search); whether SQL
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can express it [depends on the deployment](/basics/sql#no-vector-sql).
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</Warning>
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## Literals {#literals}
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| --- | --- |
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| String | `'text'` — doubled quote to escape: `'it''s'` |
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| Number | `42`, `3.14` |
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| Boolean | `TRUE`, `FALSE` |
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| Null | `NULL` |
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| Date / timestamp | `DATE '2026-01-01'`, `TIMESTAMP '2026-01-01 12:00:00'` |
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| Interval | `INTERVAL '7 days'` |
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| Array | `[1, 2, 3]` |
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Identifiers are quoted with double quotes when they need to be — a reserved word
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or a name with mixed case: `SELECT "order" FROM "MyTable"`.
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## Casting {#casting}
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```sql
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SELECT CAST(identifier AS VARCHAR) AS with_cast, identifier::VARCHAR AS with_colons
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FROM documents
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```
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Both forms work. Give each its own alias when one projection uses both: they
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produce the same expression name, and a projection refuses two columns with
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one name. `TRY_CAST` returns null instead of erroring on a value that
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will not convert, which is the one to use over a column you do not control.
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## Precedence {#precedence}
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Highest to lowest: `::` → unary `-` → `* / %` → `+ -` → `||` → comparison →
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`IS` → `NOT` → `AND` → `OR`.
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Parenthesize anything mixing `AND` and `OR`. `a OR b AND c` is `a OR (b AND c)`,
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which is rarely what was meant.
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