Sql 在子表中没有父\u id关联时删除父表中的行

我有一个名为Location的父表，它有20000行，还有两个子表，即Customer和Shop，它们大约有8000行。我想去掉两个表中都没有子表的位置。表如下所示：

父表1：位置：ID\u LocationPK，ID\u CityFK

| Zip  | ID_Location |
|------|-------------|
| 0001 | 1           |
| 0011 | 2           |
| 0002 | 3           |
| 0021 | 4           |
| 0003 | 5           |
| 0012 | 6           |

子表1：客户：客户IDPK，ID\U位置FK

| Cust_ID | ID_Location |
|---------|-------------|
| 1       | 1           |
| 2       | 3           |
| 3       | 5           |
| 4       | 2           |
| 5       | 1           |

| Shop_ID | ID_Location |
|---------|-------------|
| 1       | 1           |
| 2       | 2           |
| 3       | 6           |
| 4       | 3           |
| 5       | 1           | 

子表3：车间：车间IDPK，ID\U位置FK

| Cust_ID | ID_Location |
|---------|-------------|
| 1       | 1           |
| 2       | 3           |
| 3       | 5           |
| 4       | 2           |
| 5       | 1           |

| Shop_ID | ID_Location |
|---------|-------------|
| 1       | 1           |
| 2       | 2           |
| 3       | 6           |
| 4       | 3           |
| 5       | 1           | 

所需输出：我希望删除ID_Location=4的Location表中的行，因为它在两个子表中都没有任何子行

我所做的是

select * from Location where ID_Location not in (select ID_Location from Customer)

select * from Location where ID_Location not in (select ID_Location from Shop)

然后我对出现的行运行delete查询

delete from Location where ID_Location = 4

有没有办法运行嵌套查询来获取子表中没有任何条目的行？

这是您的查询

DELETE FROM LOC
FROM Location LOC
LEFT JOIN Customer CUST ON CUST.ID_Location = LOC.ID_Location
LEFT JOIN SHOP SH ON SH.ID_Location = LOC.ID_Location
WHERE CUST.ID IS NULL AND SH.ID IS NULL

如果要确保在适当的记录中运行，请首先运行以下命令：

SELECT LOC.*, CUST.ID, SH.ID
FROM Location LOC
LEFT JOIN Customer CUST ON CUST.ID_Location = LOC.ID_Location
LEFT JOIN SHOP SH ON SH.ID_Location = LOC.ID_Location
WHERE CUST.ID IS NULL AND SH.ID IS NULL

这是你的问题

DELETE FROM LOC
FROM Location LOC
LEFT JOIN Customer CUST ON CUST.ID_Location = LOC.ID_Location
LEFT JOIN SHOP SH ON SH.ID_Location = LOC.ID_Location
WHERE CUST.ID IS NULL AND SH.ID IS NULL

如果要确保在适当的记录中运行，请首先运行以下命令：

SELECT LOC.*, CUST.ID, SH.ID
FROM Location LOC
LEFT JOIN Customer CUST ON CUST.ID_Location = LOC.ID_Location
LEFT JOIN SHOP SH ON SH.ID_Location = LOC.ID_Location
WHERE CUST.ID IS NULL AND SH.ID IS NULL

---

从ID\u位置不在客户选择ID\u位置的位置和从店铺联盟选择ID\u位置不在店铺联盟选择ID\u位置的位置删除可能更有效，tho。从ID\u位置不在客户选择ID\u位置的位置和从店铺联盟选择ID\u位置不在店铺联盟选择ID\u位置的位置删除可能更有效，tho。