在多内部联接上更新表

Question

我正在尝试进行以下更新：

UPDATE tbl_claim

INNER JOIN tbl_mbr ON tbl_mbr.MBR_NUM = tbl_mbr_cov.MBR_NUM
INNER JOIN tbl_claim ON tbl_claim.MBR_ID = tbl_mbr.MBR_ID

SET tbl_claim.Mbr_Cov_Id = tbl_mbr_cov.MBR_COV_ID

但是我得到了：

[Err] 1066 - Not unique table/alias: 'tbl_claim'

然后我尝试了这个：

UPDATE tbl_claim AS A

INNER JOIN tbl_mbr AS C ON C.MBR_NUM = tbl_mbr_cov.MBR_NUM AS D
INNER JOIN tbl_claim AS B ON B.MBR_ID = C.MBR_ID

SET A.Mbr_Cov_Id = D.MBR_COV_ID

这给了我另一个错误：

[Err] 1064 - You have an error in your SQL syntax; check the manual that
corresponds to your MySQL server version for the right syntax to use near 
'as D INNER JOIN tbl_claim AS B ON B.MBR_ID = C.MBR_ID

但是我不知道如何为tbl_mbr_cov分配别名？

什么是正确的解决方案？

编辑：

有3个表，相关字段为：

tbl_claim:
CLAIM_ID (PK)
MBR_ID
Mbr_Cov_Id

tbl_mbr:
MBR_ID (PK)
MBR_NUM

tbl_mbr_cov:
MBR_COV_ID (PK)
MBR_NUM

如上所述，在3个表中，链接字段名称相同。 我们想要更新tbl_claim.Mbr_Cov_Id以等于tbl_mbr_cov.MBR_COV_ID中的值

这个查询可以，所以我知道联接是有意义的：

SELECT
tbl_claim.CLAIM_ID,
tbl_claim.MBR_ID,
tbl_claim.Mbr_Cov_Id,
tbl_mbr.MBR_ID,
tbl_mbr.MBR_NUM,
tbl_mbr_cov.MBR_COV_ID,
tbl_mbr_cov.MBR_NUM
FROM
tbl_mbr_cov
INNER JOIN tbl_mbr ON tbl_mbr.MBR_NUM = tbl_mbr_cov.MBR_NUM
INNER JOIN tbl_claim ON tbl_claim.MBR_ID = tbl_mbr.MBR_ID

在我看来，如果您可以运行此查询，则必须有一种简单的方法来更新tbl_claim.Mbr_Cov_Id字段。

Answer 1

尝试以下语句：

UPDATE tbl_claim

SET Mbr_Cov_Id = tbl_mbr_cov.MBR_COV_ID

FROM tbl_claim AS A
INNER JOIN tbl_mbr_cov ON A.[your_field] = tbl_mbr_cov.[your_field]
INNER JOIN tbl_mbr ON tbl_mbr.MBR_NUM = tbl_mbr_cov.MBR_NUM
INNER JOIN tbl_claim ON tbl_claim.MBR_ID = tbl_mbr.MBR_ID

WHERE [your_primary_key] = A.[your_primary_key]