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DECLARE v_a int;
DECLARE v_b int;
DECLARE i int default 0;
DECLARE done INT DEFAULT 0;
DECLARE cur1 CURSOR FOR select col_a from table_a;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done=1;
OPEN cur1;
emp_loop: LOOP
FETCH cur1 INTO v_a;
IF done=1 THEN
  LEAVE emp_loop;
ELSE
  set i=i+1;
  select i;
  select col_b into v_b from table_b where col_b=v_a;
END IF;
END LOOP emp_loop;

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µ«ÊÇÓÐÕâ¾äselect col_b into v_b from table_b where col_b=v_a;¾ÍÑ­»·ÁËÒ»´Î£¬¾Ídone=1ÁË£¡
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select count(*) into @ee from table_b where col_b=v_a
if @ee>=1 then
....
end if

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SQL code:
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done=1;


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select count(*) into @ee from table_b where col_b=v_a
if @ee>=1 then
....
end if

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