19.2.7.2. Variable SET Statement
SET var_name = expr [, var_name = expr] ...
The SET statement in stored routines is an
extended version of the general SET
statement. Referenced variables may be ones declared inside a
routine, or global system variables.
The SET statement in stored routines 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 and global and session server 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.
