This topic describes the comparison operators supported by PolarDB-X.
Comparison operators are frequently used in conditional SELECT statements. Comparison operators allow you to determine which records in a table meet the requirements. If the result of a comparison is true, 1 is returned. If the result is false, 0 is returned. If the result is uncertain, NULL is returned.
PolarDB-X supports the following comparison operators.
| Operator | Description |
|---|---|
| = | Tests whether a value is equal to another value. |
| <>, != | Tests whether a value is not equal to another value. |
| > | Tests whether a value is greater than another value. |
| < | Tests whether a value is less than another value. |
| <= | Tests whether a value is not greater than another value. |
| >= | Tests whether a value is not less than another value. |
| BETWEEN | Tests whether a value lies between two values.
>=min&&<=max |
| NOT BETWEEN | Tests whether a value does not lie between two values. |
| IN | Tests whether a value is in a set. |
| NOT IN | Tests whether a value is not in a set. |
| <=> | Tests whether two values are equal. The operands can be NULL.
Note If both operands are NULL, 1 is returned. If one operand is NULL, 0 is returned.
|
| LIKE | This operator is used for fuzzy matching. |
| REGEXP or RLIKE | This operator is used for matching that is based on regular expressions. |
| IS NULL | Tests whether a value is NULL. |
| IS NOT NULL | Tests whether a value is not NULL. |