select hex(@a); hex(@a) NULL select hex(@a); hex(@a) 610063 set global init_connect="set @a=2;set @b=3"; select @a, @b; @a @b 2 3 set GLOBAL init_connect=DEFAULT; select @a; @a NULL set global init_connect="drop table if exists t1; create table t1(a char(10));\ insert into t1 values ('\0');insert into t1 values('abc')"; select hex(a) from t1; hex(a) 00 616263 set GLOBAL init_connect="adsfsdfsdfs"; select @a; Got one of the listed errors drop table t1;