mysql 存儲過程迭代獲取數據

項目中有需要根據ParentId查詢ChildId,由於mysql本身不能提供迭代的函數。因此使用存儲過程迭代查詢。記錄在此，下次可以直接複製使用。

DECLARE _effectrow int;
  DECLARE _max int;
  set  _max=0;
  SET _effectrow=1;
  #獲取所有商品種類的頂級ID
  DROP TEMPORARY TABLE IF EXISTS temp_catagory;
  CREATE TEMPORARY TABLE temp_catagory(catagoryid bigint,level int);
  DROP TEMPORARY TABLE IF EXISTS temp_mid_catagory;
  CREATE TEMPORARY TABLE temp_mid_catagory(catagoryid bigint);
  
  INSERT temp_catagory(catagoryid,level) SELECT id,0 FROM catalogs WHERE CompanyId=_companyid AND ParentId=0;
  outer_label:   #設置一個標記
    WHILE _effectrow>0 DO 
      set _max=_max+1;
      IF _max>10 THEN 
        LEAVE outer_label ;
      END IF;
      #獲取所有商品種類的子商品種類
      INSERT temp_mid_catagory(catagoryid) 
        SELECT id FROM catalogs a WHERE  CompanyId=_companyid AND 
        EXISTS(SELECT 1 FROM temp_catagory b WHERE a.ParentId=b.catagoryid AND LEVEL=(_max-1));
      SET _effectrow=ROW_COUNT();

      IF _effectrow>0 THEN
         INSERT temp_catagory(catagoryid,level) SELECT catagoryid,_max  FROM temp_mid_catagory;
         DELETE FROM temp_mid_catagory;
      END IF;
    END WHILE;
       # SELECT * FROM temp_catagory;