MySQL 重复数据删除语句

墨着染霜华2026-04-12 14:38

方案 1：有自增主键 id（推荐，最安全）

假设你的表有主键：id（没有就用方案 2）

复制代码

DELETE a
FROM leave_sdxw a
JOIN (
    -- 找出每组重复数据中 最小的id之外的所有记录
    SELECT tenant_id, sddm, fill_vpdm, MIN(id) AS keep_id
    FROM leave_sdxw
    WHERE fill_vpdm IS NOT NULL
    GROUP BY tenant_id, sddm, fill_vpdm
    HAVING COUNT(*) > 1
) b ON a.tenant_id = b.tenant_id 
   AND a.sddm = b.sddm 
   AND a.fill_vpdm = b.fill_vpdm 
   AND a.id > b.keep_id; -- 只删大于最小id的重复数据

方案 2：没有主键 / 唯一列（不推荐，但能用）

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-- 先创建临时表存储重复组合
CREATE TEMPORARY TABLE tmp_repeat AS
SELECT tenant_id, sddm, fill_vpdm
FROM leave_sdxw
WHERE fill_vpdm IS NOT NULL
GROUP BY tenant_id, sddm, fill_vpdm
HAVING COUNT(*) > 1;

-- 删除重复（会每组只留一条，取决于数据库存储顺序）
DELETE a
FROM leave_sdxw a
JOIN tmp_repeat b 
ON a.tenant_id = b.tenant_id 
AND a.sddm = b.sddm 
AND a.fill_vpdm = b.fill_vpdm;

-- 删除临时表
DROP TEMPORARY TABLE IF EXISTS tmp_repeat;

执行前建议 先执行查询确认要删的数据，不要直接删：

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-- 先查询，确认重复数据
SELECT a.*
FROM leave_sdxw a
JOIN (
    SELECT tenant_id, sddm, fill_vpdm, MIN(id) AS keep_id
    FROM leave_sdxw
    WHERE fill_vpdm IS NOT NULL
    GROUP BY tenant_id, sddm, fill_vpdm
    HAVING COUNT(*) > 1
) b ON a.tenant_id = b.tenant_id 
   AND a.sddm = b.sddm 
   AND a.fill_vpdm = b.fill_vpdm 
   AND a.id > b.keep_id;

总结

优先用方案 1（带主键 id），安全、高效、不会删光数据
执行删除前一定要先查询预览