DELIMITER $$
DROP PROCEDURE IF EXISTS Pro_Compare_Tab$$
CREATE PROCEDURE Pro_Compare_Tab(IN v_DB1 VARCHAR(45), #一号数据库
                                 IN v_DB2 VARCHAR(45), #二号数据库
                                 IN v_DB3 VARCHAR(45), #三号数据库
                                 IN v_Table VARCHAR(45), #3个数据库中都有的表名
                                 IN nOffset INT) #主键偏移量
BEGIN
DECLARE v_KEYS  VARCHAR(80);
DECLARE v_sql   VARCHAR(1000);
DECLARE v_tmp   VARCHAR(100);
DECLARE v_tmp2  VARCHAR(100);
DECLARE v_SPACE VARCHAR(45);
DECLARE v_PKeyExist INT DEFAULT 0;
DECLARE n_flag,nNumKeys,n_Index INT DEFAULT 0;
DECLARE done INT DEFAULT 0;
DECLARE cur_pkey CURSOR FOR SELECT
      c.TABLE_NAME,MAX(c.COLUMN_NAME) COLUMN_NAME
    FROM
      INFORMATION_SCHEMA.TABLE_CONSTRAINTS AS t,
      INFORMATION_SCHEMA.KEY_COLUMN_USAGE AS c
    WHERE
      t.TABLE_NAME = c.TABLE_NAME
      AND t.TABLE_SCHEMA = v_DB1
      AND t.TABLE_NAME = v_Table
      AND t.CONSTRAINT_TYPE = 'PRIMARY KEY'
      GROUP BY c.TABLE_NAME
      HAVING MAX(c.ORDINAL_POSITION) = 1;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = 1;
  OPEN cur_pkey;
  SET n_Index = 1;
  LOOP_FLAG:LOOP
    FETCH cur_pkey INTO v_SPACE,v_KEYS;
    IF done = 1 THEN LEAVE LOOP_FLAG;
    END IF;
      SET v_PKeyExist = 1;
      IF n_Index = 1 THEN
        SET @v_tmp = CONCAT('A.',v_KEYS,' = B.',v_KEYS);
        SET @v_tmp2 = CONCAT('A.',v_KEYS,' <> B.',v_KEYS);
      ELSE
        SET @v_tmp = CONCAT(v_tmp,'AND A.',v_KEYS,' = B.',v_KEYS);
        SET @v_tmp2 = CONCAT(v_tmp2,' OR A.',v_KEYS,' <> B.',v_KEYS);
      END IF;
      SET n_Index = n_Index + 1;
    END LOOP;
  CLOSE cur_pkey;
  IF v_PKeyExist <> 0 THEN
  SET @v_sql = CONCAT('SELECT 1 into @aa FROM information_schema.TABLES where table_schema = \'',v_DB1,
  '\' and table_name = \'',v_Table,'_Back\'');
  PREPARE stml FROM @v_sql;
  EXECUTE stml;
  IF @aa IS NOT NULL THEN
    SET @v_sql = CONCAT('TRUNCATE TABLE ',v_DB1,'.',v_Table,'_Back');
    PREPARE stml FROM @v_sql;
    EXECUTE stml;
    SET @v_sql =CONCAT('INSERT INTO ',v_DB1,'.',v_Table,'_Back SELECT * FROM ',v_DB1,'.',v_Table,
    ' A LEFT JOIN ',v_DB2,'.',v_Table,' B on ',v_tmp,' WHERE B.',v_KEYS,' IS NULL;');
    PREPARE stml FROM @v_sql;
    EXECUTE stml;
    COMMIT;
  ELSE
    SET @v_sql =CONCAT( 'CREATE TABLE ',v_DB1,'.',v_Table,'_Back SELECT A.* FROM ',v_DB1,'.',v_Table,
    ' A LEFT JOIN ',v_DB2,'.',v_Table,' B ON ',v_tmp,' WHERE B.',v_KEYS,' IS NULL;');
    PREPARE stml FROM @v_sql;
    EXECUTE stml;
    COMMIT;
  END IF;
  SET @v_sql =CONCAT( 'UPDATE ',v_DB1,'.',v_Table,'_Back A SET ',v_KEYS,' = ',v_KEYS,' + ',V_OFFSET,' WHERE A.',v_KEYS,' < ',V_OFFSET);
  PREPARE stml FROM @v_sql;
  EXECUTE stml;
  COMMIT;
  SET @v_sql =CONCAT( 'INSERT INTO ',v_DB3,'.',v_Table,'A  SELECT * FROM ',v_DB1,'.',v_Table,'_Back B WHERE ',v_tmp2);
  PREPARE stml FROM @v_sql;
  EXECUTE stml;
  COMMIT;
  SET @v_sql =CONCAT( 'DROP TABLE ',v_DB1,'.',v_Table,'_Back');
  PREPARE stml FROM @v_sql;
  EXECUTE stml;
  COMMIT;
  END IF;
END$$
DELIMITER ;