DSL Operators

Two extension traits add DuckDB’s operators that stock Diesel lacks. Both are blanket-implemented for every expression and come in through the DSL prelude:

use diesel::prelude::*;
use better_duck_diesel::dsl::*;

Text matching — `DuckTextExpressionMethods`

The right-hand side binds as Text. These are DuckDB’s string-matching operators:

Method	SQL	Meaning
`.ilike(pat)`	`ILIKE`	case-insensitive `LIKE`
`.not_ilike(pat)`	`NOT ILIKE`	negated case-insensitive `LIKE`
`.similar_to(re)`	`SIMILAR TO`	whole-string regex match
`.not_similar_to(re)`	`NOT SIMILAR TO`	negated whole-string regex
`.glob(pat)`	`GLOB`	Unix `*`/`?`/`[…]` glob (case-sensitive)
`.regexp_matches(re)`	`~`	POSIX regex match (operator form)
`.not_regexp_matches(re)`	`!~`	negated POSIX regex
`.starts_with_op(pre)`	`^@`	prefix test

let hits: Vec<i32> = products::table
    .filter(products::name.ilike("wid%"))
    .select(products::id)
    .load(&mut conn)?;

let globbed: Vec<String> = products::table
    .filter(products::name.glob("w*t"))
    .select(products::name)
    .load(&mut conn)?;

.regexp_matches() (an operator method producing the ~ operator) and the free function regexp_matches(s, pat) (which emits the regexp_matches(...) call — see String functions) are distinct items that happen to share a name. Pick the method for operator-style predicates, the function to call the SQL function.

Null-safe comparison — `DuckExpressionMethods`

Method	SQL	Meaning
`.is_distinct_from(x)`	`IS DISTINCT FROM`	null-safe `<>` (two NULLs compare equal)
`.is_not_distinct_from(x)`	`IS NOT DISTINCT FROM`	null-safe `=`

let changed: Vec<i32> = items::table
    .filter(items::new_val.is_distinct_from(items::old_val)) // treats NULLs sanely
    .select(items::id)
    .load(&mut conn)?;

Unlike =/<>, these never yield NULL: NULL IS NOT DISTINCT FROM NULL is true, and 1 IS DISTINCT FROM NULL is true. Use them when either side can be NULL and you want set-style equality.

String functions

Function forms of regex and matching.

Select

Where predicates are used.

DSL overview

The prelude and the rest of the DSL.

Delete

Operators in a delete filter.

Getting Started

CRUD

DuckDB SQL DSL

Types & Pooling

Text matching — `DuckTextExpressionMethods`

Null-safe comparison — `DuckExpressionMethods`

See also

String functions

Select

DSL overview

Delete

​Text matching — DuckTextExpressionMethods

​Null-safe comparison — DuckExpressionMethods

​See also

String functions

Select

DSL overview

Delete

Text matching — `DuckTextExpressionMethods`

Null-safe comparison — `DuckExpressionMethods`

See also