SET var_name = expr [, var_name = expr] ...

The SET statement in stored programs is an extended version of the general SET statement (see Section 12.4.4, “SET Syntax”). Each var_name may refer to a local variable declared inside a stored program, a system variable, or a user-defined variable.

The SET statement in stored programs is implemented as part of the pre-existing SET syntax. This enables an extended syntax of SET a=x, b=y, ... where different variable types (locally declared variables, global and session system variables, user-defined variables) can be mixed. This also enables combinations of local variables and some options that make sense only for system variables; in that case, the options are recognized but ignored.