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    PolarDB:Operators

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    PolarDB:Operators

    Last Updated:Mar 28, 2026

    PolarDB-X supports logical, arithmetic, comparison, bitwise, and assignment operators. This page documents each operator type and the operator precedence rules that govern expression evaluation.

    On this page:

    Logical operators

    OperatorDescription
    AND, &&Logical AND
    NOT, !Logical NOT
    ||, ORLogical OR
    XORLogical XOR

    Arithmetic operators

    OperatorDescription
    /, DIVDivision
    %, MODReturns the remainder when one number is divided by another
    +Addition
    *Multiplication
    -Subtraction

    Comparison operators

    Comparison operators are commonly used in conditional SELECT statements to filter rows. Each comparison returns one of three values:

    • 1 — the comparison is true

    • 0 — the comparison is false

    • NULL — the result is unknown (typically when one or both operands are NULL)

    OperatorDescription
    =Equal to
    <>, !=Not equal to
    >Greater than
    <Less than
    <=Less than or equal to
    >=Greater than or equal to
    BETWEENTrue if the value is within the range, inclusive: value >= min AND value <= max
    NOT BETWEENTrue if the value is outside the range
    INTrue if the value is in a set
    NOT INTrue if the value is not in a set
    <=>NULL-safe equality: returns 1 if both operands are NULL, returns 0 if one operand is NULL
    LIKEPattern matching using % and _ wildcards
    REGEXP, RLIKEPattern matching using regular expressions
    IS NULLTrue if the value is NULL
    IS NOT NULLTrue if the value is not NULL
    The ordinary equality operator (=) returns NULL when either operand is NULL, which may produce unexpected results in WHERE clauses. Use <=> when comparing columns that may contain NULL values.

    Bitwise operators

    OperatorDescription
    &Bitwise AND
    ~Bitwise NOT
    |Bitwise OR
    ^Bitwise XOR
    <<Left shift
    >>Right shift

    Assignment operators

    PolarDB-X supports the = assignment operator, used primarily in the SET clause of UPDATE statements.

    PolarDB-X does not support the := assignment operator.

    Operator precedence

    The following table lists operators in descending order of precedence (highest first). Operators at the same precedence level are evaluated left to right.

    PrecedenceOperatorType
    15!Unary (prefix)
    14- (unary minus), ~Unary (prefix)
    13^Binary
    12*, /, %, MODBinary
    11+, -Binary
    10<<, >>Binary
    9&Binary
    8|Binary
    7= (comparison), <=>, >, >=, <, <=, <>, !=, IS, LIKE, REGEXP, INBinary
    6BETWEENTernary
    5NOTUnary (prefix)
    4AND, &&Binary
    3XORBinary
    2OR, ||Binary
    1= (assignment)Binary

    IN and NOT IN precedence

    IN and NOT IN have higher precedence than the = comparison operator. The following examples, run on MySQL 5.7.19, demonstrate this behavior. PolarDB-X follows the same precedence rule.

    SELECT BINARY 'a' = 'a' IN (1, 2, 3);

    Result:

    +-------------------------------+
| binary 'a' = 'a' in (1, 2, 3) |
+-------------------------------+
|                             1 |
+-------------------------------+
1 row in set, 1 warning (0.01 sec)

    The expression is evaluated as BINARY 'a' = ('a' IN (1, 2, 3)), not (BINARY 'a' = 'a') IN (1, 2, 3), because IN has higher precedence than =.

    SELECT 1 IN (1, 2, 3) = 'a';

    Result:

    +----------------------+
| 1 in (1, 2, 3) = 'a' |
+----------------------+
|                    0 |
+----------------------+
1 row in set, 1 warning (0.00 sec)

    Both queries produce Warning 1292: Truncated incorrect DOUBLE value: 'a'.

    MySQL compatibility

    PolarDB-X is compatible with MySQL operator syntax with the following exception:

    OperatorMySQL supportPolarDB-X support
    := (assignment)SupportedNot supported