variables.md

Variables

ZetaSQL specifies the syntax for the variable statements SET and UNSET.

VARIABLE TYPES

There are three primary variable types: runtime variables, query parameters, and system variables. Each can be set and unset with the SET and UNSET commands. Additionally, query parameters are prefixed with a single @ symbol and system variables are prefixed with @@.

The variable names must be valid sql identifiers.

SET

Sets a variable.

SET runtime_variable = constant_value;
SET @query_parameter = constant_value;
SET @@system_variable = constant_value;

UNSET

Unsets a variable.

UNSET runtime_variable;
UNSET @query_parameter;
UNSET @@system_variable;