要删除数据库中字段相同但特定列值为空的重复行,可以使用以下几种方法,具体取决于您使用的数据库系统:
WITH CTE AS (
SELECT *,
ROW_NUMBER() OVER (
PARTITION BY 字段1, 字段2, 字段3 /* 需要判断重复的字段 */
ORDER BY CASE WHEN 特定列 IS NULL THEN 1 ELSE 0 END /* 优先保留非空值 */
) AS RowNum
FROM 表名
)
DELETE FROM CTE WHERE RowNum > 1;
DELETE t1 FROM 表名 t1
INNER JOIN 表名 t2
WHERE
t1.id > t2.id /* 假设有自增ID,保留ID较小的记录 */
AND t1.字段1 = t2.字段1
AND t1.字段2 = t2.字段2
AND /* 其他判断重复的字段 */
(t1.特定列 IS NULL OR t2.特定列 IS NULL);
DELETE FROM 表名
WHERE id IN (
SELECT id FROM (
SELECT id,
ROW_NUMBER() OVER (
PARTITION BY 字段1, 字段2, 字段3
ORDER BY CASE WHEN 特定列 IS NULL THEN 1 ELSE 0 END
) AS rn
FROM 表名
) t
WHERE t.rn > 1
);
DELETE FROM 表名
WHERE ROWID IN (
SELECT ROWID FROM (
SELECT ROWID,
ROW_NUMBER() OVER (
PARTITION BY 字段1, 字段2, 字段3
ORDER BY CASE WHEN 特定列 IS NULL THEN 1 ELSE 0 END
) AS rn
FROM 表名
)
WHERE rn > 1
);
BEGIN TRANSACTION;
-- 执行删除语句
-- 检查结果
COMMIT; -- 或 ROLLBACK;
您需要根据具体的数据库类型和表结构调整上述SQL语句。如果您能提供更具体的数据库环境和表结构信息,我可以给出更精确的解决方案。