> ## Documentation Index
> Fetch the complete documentation index at: https://docs.kinetica.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Predicates

*Predicate* are generally used within a SQL `WHERE` clause to query records.
They compare the values of two or more *expressions*; whenever a record meets
the criteria defined in a *predicate clause* it will be marked as eligible
to be part of the query result set.  If it meets all *predicate clauses* defined
within a query, it will be returned in the result set.

A single *predicate clause* may use a simple *predicate operator* to compare the
values of two *expressions* or a more complex *predicate clause* form.  A
*compound predicate clause* uses a *compound predicate operator* to link
together multiple *predicate clauses* to further refine a result set.

Unlimited-width ([non-charN](/content/concepts/types#types-chart)) strings can only be used within
equality-based predicates, e.g. `=`, `IN`, etc.

<a id="sql-pred-op" />

## Predicate Operators

* `=` *equality*
* `!=` or `<>` *inequality*
* `<` *less than*
* `<=` *less than or equal to*
* `>` *greater than*
* `>=` *greater than or equal to*

## Predicate Clauses

In the following list of *predicate clauses*, `ref_expr` is the reference
expression to apply the predicate to; note that `EXISTS` has no reference
expression.

| Predicate Clause                                       | Description                                                                                                                                                                                                                     |
| ------------------------------------------------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `<expr_a> <pred_op> <expr_b>`                          | Matches records where `expr_a` relates to `expr_b` according to [predicate operator](/content/sql/query/predicates#sql-pred-op) `pred_op`.                                                                                      |
| `<ref_expr> <pred_op> ALL (<select statement>)`        | Matches records where the reference expression `ref_expr` relates to *all* of the results of `select statement` according to the [predicate operator](/content/sql/query/predicates#sql-pred-op) `pred_op`                      |
| `<ref_expr> <pred_op> ANY (<select statement>)`        | Matches records where the reference expression `ref_expr` relates to *any* of the results of `select statement` according to the [predicate operator](/content/sql/query/predicates#sql-pred-op) `pred_op`                      |
| `<ref_expr> [NOT] BETWEEN <begin_expr> AND <end_expr>` | Matches records where the reference expression `ref_expr` is (or is `NOT`) between the values of `begin_expr` and `end_expr`, inclusive                                                                                         |
| `<ref_expr> [NOT] IN (<match_list>)`                   | Matches records where the reference expression `ref_expr` is (or is `NOT`) in the `match_list` list of match values.  The list can either be a comma-separated list of terms/expressions or the result of a `SELECT` statement. |
| `<ref_expr> IS [NOT] NULL`                             | Matches records where the reference expression `ref_expr` is (or is `NOT`) *null*.                                                                                                                                              |
| `[NOT] EXISTS (<select statement>)`                    | Matches records where `select statement` returns 1 or more records.                                                                                                                                                             |

## Compound Predicate Operators

| Predicate Operator      | Description                                                 |
| ----------------------- | ----------------------------------------------------------- |
| `<pred_a> AND <pred_b>` | Matches records where both `pred_a` & `pred_b` are *true*   |
| `<pred_a> OR <pred_b>`  | Matches records where either `pred_a` or `pred_b` is *true* |
| `NOT <pred_b>`          | Matches records where `pred` is *false*                     |