SET var_name = expr [, var_name = expr] ...
The SET statement in stored programs is an extended version of the general SET statement (see [HELP SET]). Referenced variables may be ones declared inside a stored program, global system variables, or user-defined variables.
The SET statement in stored programs is implemented as part of the pre-existing SET syntax. This allows an extended syntax of SET a=x, b=y, ... where different variable types (locally declared variables, global and session server variables, user-defined variables) can be mixed. This also allows combinations of local variables and some options that make sense only for system variables; in that case, the options are recognized but ignored.
When setting several variables using the columns returned by a query, SELECT INTO should be preferred.
To set many variables to the same value, the LAST_VALUE() function can be used.