sql - 试图从加入中删除，我知道我有时髦的间距，我知道我有重复的 IMEI

Question

DELETE dbo.bBoxDetail
FROM dbo.bBoxDetail AS BD
INNER JOIN dbo.bBoxHeader AS BH ON LTRIM(RTRIM(BD.bBoxDetailId)) = LTRIM(RTRIM(BH.bBoxId))
WHERE LTRIM(RTRIM(BD.ESNs)) = (SELECT LTRIM(RTRIM(IMEI)) FROM dbo.tmpIMEI)

我收到此错误：

消息 512，级别 16，状态 1，第 1 行子查询返回超过 1 个值。当子查询跟随 =、!=、<、<=、>、>= 或子查询用作表达式时，这是不允许的。

BD.ESNsisNVARCHAR(50)和IMEIisNVARCHAR(30)我有重复ESNs的，我想删除所有ESNs匹配的SELECT ... IMEI

Answer 1

在 WHERE 子句中使用IN运算符

DELETE dbo.bBoxDetail
FROM dbo.bBoxDetail AS BD INNER JOIN dbo.bBoxHeader AS BH ON LTRIM(RTRIM(BD.bBoxDetailId)) = LTRIM(RTRIM(BH.bBoxId))
WHERE LTRIM(RTRIM(BD.ESNs)) IN (SELECT LTRIM(RTRIM(IMEI)) FROM dbo.tmpIMEI)

但首选选项是EXISTS运算符

DELETE dbo.bBoxDetail
FROM dbo.bBoxDetail AS BD INNER JOIN dbo.bBoxHeader AS BH ON LTRIM(RTRIM(BD.bBoxDetailId)) = LTRIM(RTRIM(BH.bBoxId))
WHERE EXISTS (
              SELECT 1
              FROM dbo.tmpIMEI
              WHERE LTRIM(RTRIM(BD.ESNs)) = LTRIM(RTRIM(IMEI))
              )

Answer 2

如果您阅读错误

消息 512，级别 16，状态 1，第 1 行子查询返回超过 1 个值。当子查询跟随 =、!=、<、<=、>、>= 或子查询用作表达式时，这是不允许的。

注意子查询返回超过 1 个值，因为这是错误，您从子查询返回任意数量的行：

正确的 SQL 如下：

DELETE dbo.bBoxDetail
FROM dbo.bBoxDetail AS BD
INNER JOIN dbo.bBoxHeader AS BH ON LTRIM(RTRIM(BD.bBoxDetailId)) = LTRIM(RTRIM(BH.bBoxId))
WHERE LTRIM(RTRIM(BD.ESNs)) = (SELECT TOP 1 LTRIM(RTRIM(IMEI)) FROM dbo.tmpIMEI)