SQL查询表中重复记录的几种情况
例如现在有个商品表t_product
表结构如图所示
- 根据单个字段查询重复记录，查询表中productName字段重复的记录
SELECT
*
FROM
t_product
WHERE
productName IN (
SELECT
productName
FROM
t_product
GROUP BY
productName
HAVING
count(productName) > 1
)
- 根据多个字段查询重复记录,查询表中productName，productStock相同的数据
SELECT
*
FROM
t_product p
WHERE
(p.productName, p.productStock) IN (
SELECT
productName,
productStock
FROM
t_product
GROUP BY
productName,
productStock
HAVING
count(*) > 1
)
