guardar un dato de una tabla en una variable

[dacroma]

El error dice:

Código MySQL:

you have an error in your SQL sintax; check de manual that corresponds to your 
mysql server version for de rigth sintax to use near '=0;
num=(select total from factura where cod_factura=4); select num; end;' at line 3
 

y cuando lo hago de forma diferente:

Código MySQL:

delimiter //
create procedure funcionX( param int)
begin
param=0;
param=(select total from cliente where id_cliente=4); 
 
if param>3000 then
select "el valor es apto";
else 
select "el valor no es apto";
end if;
end; 
//
delimiter ;
you have an error in your SQL sintax; check de manual that corresponds to your 
mysql server version for de rigth sintax to use near 'param=0;
param=(select total from factura where cod_factura=4); select param; end;' at line 3
 

ò

Código MySQL:

delimiter //
create procedure funcionX( param int)
begin
set @var=0;
@var=(select total from cliente where id_cliente=param); 
 
if @var > 3000 then
select "el valor es apto";
else 
select "el valor no es apto";
end if;
end;
//
 
you have an error in your SQL sintax; check de manual that corresponds to your 
mysql server version for de rigth sintax to use near '@var=0;
@var=(select total from factura where cod_factura=param); select param; end;' at line 3
delimiter ;