将数据从一个表更新到另一个表失败

Question

I have two tables in two systems both have the same structure. I want update the data in one table to other

update Table1
set VIEW_CD = cmn.VIEW_CD,
    VIEW_DETAIL = cmn.VIEW_DETAIL 
FROM dbo.Table1 tbl
INNER JOIN dbo.Table2 cmn ON tbl.id = cmn.id

Both the columns in both the tables are null columns but I am ending up with the exception

Cannot insert the value NULL into column column does not allow nulls. INSERT fails.

Answer 1

I believe the problem is that you have NOT NULL constraint on Table1 , you should drop it :

ALTER TABLE dbo.Table1 ALTER COLUMN VIEW_CD <columnType> NULL

Or this:

ALTER TABLE dbo.Table1 ALTER VIEW_CD DROP NOT NULL

And then run the query once again.

Answer 2

Try this :

update Table1
    set     VIEW_CD = cmn.VIEW_CD,
    VIEW_DETAIL = cmn.VIEW_DETAIL 
    FROM dbo.Table1 tbl
    INNER JOIN dbo.Table2 cmn ON tbl.id = cmn.id
where VIEW_CD  IS NOT NULL AND VIEW_DETAIL IS NOT NULL

The above will update Table1 with all the records from Table2 where the records doesn't contain any NULL values.