Question

如何让所有列（在DB中）只有NULL值。？

如果有2个表格： T1

A        B

1       NULL
2       NULL
NULL    NULL

和T2

C        D

NULL    920
NULL    NULL
NULL    2323

我想要返回B和C

Answer 1

你的意思是B和C吗？

尝试：

Declare @schemaname varchar(255), @tablename varchar(255)

DECLARE table_cur cursor for
SELECT s.name,t.name
FROM sys.tables t Join sys.schemas s on t.schema_id=s.schema_id

OPEN table_cur
FETCH NEXT FROM table_cur into @schemaname, @tablename
WHILE @@FETCH_STATUS = 0
BEGIN

    Declare @col varchar(255), @cmd varchar(max)

    DECLARE column_cur cursor for
    SELECT COLUMN_NAME FROM INFORMATION_SCHEMA.COLUMNS
        WHERE TABLE_NAME = @tablename

    OPEN column_cur

    FETCH NEXT FROM column_cur into @col

    WHILE @@FETCH_STATUS = 0
    BEGIN
        SELECT @cmd = 'IF NOT EXISTS (SELECT top 1 * FROM ' + @schemaname + '.' + @tablename +' WHERE [' + @col + '] IS NOT NULL) BEGIN print '' Table: ' + @tablename + ', Column: ' + @col + ''' end'
        EXEC(@cmd)

        FETCH NEXT FROM column_cur into @col
    END

    CLOSE column_cur
    DEALLOCATE column_cur

    FETCH NEXT FROM table_cur into @schemaname, @tablename

END


CLOSE table_cur
DEALLOCATE table_cur

返回仅具有NULL值的列

1 个答案: