Question

大家好，我有桌子：

Expected Date|  00:00   |  01:00 |  02:00   |03:00|
20160428     |  11179   |  [NULL]|  [NULL]| [NULL]
20160428     |  11181   |  [NULL]   |[NULL] |[NULL]
20160428     |  11182   |  [NULL]   |[NULL] |[NULL]
20160426     |  [NULL]  |  [NULL]   |[NULL] |11180                         
20160426     |  [NULL]  |  [NULL]   |[NULL] |11189

表动态数据。如何选择只获取包含数据的列（00:00和03:00），但不选择NULL垂直列（01:00和02:00）。

我想要的是什么：

|Expected Date |  00:00  | 03:00
|20160428      |  11179   | [NULL]
|20160428      |  11181   | [NULL]
|20160428      |  11182   | [NULL]
|20160426      |  [NULL]  | 11180
|20160426      |  [NULL]  | 11189

Answer 1

DECLARE getinfo cursor for
SELECT c.name FROM sys.tables t JOIN sys.columns c ON t.Object_ID = c.Object_ID
WHERE t.Name = '<table_name>'

OPEN getinfo

FETCH NEXT FROM getinfo into @col

WHILE @@FETCH_STATUS = 0
BEGIN
    SELECT @cmd = 'IF NOT EXISTS (SELECT top 1 * FROM <table_name> WHERE [' + @col + '] IS NULL) BEGIN SELECT @tmp = ''' + @col + ','' end'
    exec sp_executesql @cmd, N'@tmp varchar(30) out', @tmp out
    if @tmp IS NOT NULL
    BEGIN
        SELECT @nonNullCol = CONCAT(@nonNullCol, @tmp)
    END
    SELECT @tmp = null
    FETCH NEXT FROM getinfo into @col
END

CLOSE getinfo
DEALLOCATE getinfo
PRINT @nonNullCol

SELECT @cmd = 'SELECT ' + LEFT(@nonNullCol, LEN(@nonNullCol)-1) + ' FROM <table_name>'
EXEC(@cmd)

DB2不选择NULL垂直列

1 个答案: