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  • sql

    删除重复数据,保留最小数据

    SELECT * FROM complete where dm in (SELECT dm FROM complete GROUP BY dm HAVING count(1)>1);
    DELETE FROM complete WHERE id in (SELECT id from (SELECT id FROM complete where dm in (SELECT dm FROM complete GROUP BY dm HAVING count(1)>1) AND id NOT in (SELECT min(id) FROM complete GROUP BY dm HAVING count(1)>1)) a);
      

    更改表数据类型

    ALTER TABLE `all_record`
    ENGINE=MyISAM;

    ALTER TABLE `all_record`
    ENGINE=InnoDB;

    存储过程更新数据拿下一条记录

    BEGIN
    DECLARE udm VARCHAR(64);
    DECLARE in_data_time int(10);
    DECLARE in_zdf DECIMAL(10,2);
    DECLARE in_done int;
    DECLARE done int;
    DECLARE u_c CURSOR FOR SELECT dm FROM all_record GROUP BY dm ;
    DECLARE CONTINUE HANDLER FOR NOT FOUND SET done=1;
    OPEN u_c;
    c:LOOP
    FETCH u_c INTO udm;
    if done=1 THEN
    LEAVE c;
    ELSE
    SET @old_data_time = 0;
    BEGIN
    DECLARE in_u_c CURSOR FOR SELECT data_time,zdf FROM all_record WHERE dm=udm ;
    DECLARE CONTINUE HANDLER FOR NOT FOUND SET in_done=1;
    OPEN in_u_c;
    in_c:LOOP
    FETCH in_u_c INTO in_data_time,in_zdf;
    if in_done=1 THEN
    LEAVE in_c;
    ELSE
    UPDATE all_record SET next_result=in_zdf WHERE next_result=-110 AND dm=udm AND data_time=@old_data_time;
    SET @old_data_time=in_data_time;
    end if;
    END LOOP in_c;
    CLOSE in_u_c;
    SET in_done=0;
    END;
    end if;
    END LOOP c;
    CLOSE u_c;
    END

    存储过程拿上一条记录

    BEGIN
    DECLARE udm VARCHAR(64);
    DECLARE in_data_time int(10);
    DECLARE in_zxj DECIMAL(10,2);
    DECLARE in_done int;
    DECLARE done int;
    DECLARE u_c CURSOR FOR SELECT dm FROM all_record GROUP BY dm ;
    DECLARE CONTINUE HANDLER FOR NOT FOUND SET done=1;
    OPEN u_c;
    c:LOOP
    FETCH u_c INTO udm;
    if done=1 THEN
    LEAVE c;
    ELSE
    SET @old_zxj = 0;
    BEGIN
    DECLARE in_u_c CURSOR FOR SELECT data_time,zxj FROM all_record WHERE dm=udm ;
    DECLARE CONTINUE HANDLER FOR NOT FOUND SET in_done=1;
    OPEN in_u_c;
    in_c:LOOP
    FETCH in_u_c INTO in_data_time,in_zxj;
    if in_done=1 THEN
    LEAVE in_c;
    ELSE
    UPDATE all_record SET zs=@old_zxj WHERE zs=-11 AND dm=udm AND data_time=in_data_time;
    SET @old_zxj=in_zxj;
    end if;
    END LOOP in_c;
    CLOSE in_u_c;
    SET in_done=0;
    END;
    end if;
    END LOOP c;
    CLOSE u_c;
    END

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  • 原文地址:https://www.cnblogs.com/nowphp/p/6678436.html
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