Question

我正在尝试使用此处显示的示例在临时表中设置值：SQL output: Is it possible to create a temporary output column?

我创建了我的初始表，我使用列名来建立新列值“operdesc”的总体数。

这是我的工作表查询，其中我获得了我需要的COLUMN_NAME值。我想添加一个临时列“OPERAND”：

SELECT     COLUMN_NAME, DATA_TYPE, 'OPERAND' AS TempField, 
                  CASE WHEN COLUMN_NAME = 'Street' THEN '=' WHEN COLUMN_NAME = 'Town' THEN 'CW' END AS OPERAND FROM         INFORMATION_SCHEMA.COLUMNS WHERE    (TABLE_SCHEMA = 'dbo') AND (TABLE_NAME = 'Customers') ORDER BY COLUMN_NAME

但是，我想更进一步，并使用临时连接简化它。我按照这个例子：SQL output: Is it possible to create a temporary output column?但我挂了我的剧本。这就是我所拥有的，但它不起作用，希望我很接近：

WITH XOperLU (xopername, xoperdesc)
 AS
 (
  SELECT xopername, CAST(xoperdesc AS VARCHAR(20))
    FROM (
          VALUES ('Street', 'SS'), 
                 ('Town', 'TW')                    
         ) AS XOperLU (xopername, xoperdesc)
 ) SELECT COLUMN_NAME as T1.COLUMN_NAME, DATA_TYPE as T1.DATA_TYPE, S1.xoperdesc AS Description FROM INFORMATION_SCHEMA.COLUMNS  AS T1 WHERE    (TABLE_SCHEMA = 'dbo') AND (TABLE_NAME = 'Clients') 
   INNER JOIN XOperLU AS S1
      ON S1.xopername = T1.COLUMN_NAME;

“客户”表是一个视图。

提前多多谢谢！

Answer 1

你几乎没问题，但你在列别名而不是列中使用了T1别名，最重要的是你在WHERE之前有JOIN。这有效：

WITH XOperLU (xopername, xoperdesc)
 AS
 (
  SELECT xopername, CAST(xoperdesc AS VARCHAR(20))
    FROM (
          VALUES ('Street', 'SS'), 
                 ('Town', 'TW')                    
         ) AS XOperLU (xopername, xoperdesc)
 ) SELECT T1.COLUMN_NAME as COLUMN_NAME, T1.DATA_TYPE as DATA_TYPE, S1.xoperdesc AS Description FROM INFORMATION_SCHEMA.COLUMNS  AS T1 
   INNER JOIN XOperLU AS S1
      ON S1.xopername = T1.COLUMN_NAME
      WHERE    (TABLE_SCHEMA = 'dbo') AND (TABLE_NAME = 'Clients')

如果要查看没有指定描述的所有其他列要设置为某些内容，例如'XX'，你可以使用左连接：

WITH XOperLU (xopername, xoperdesc)
 AS
 (
  SELECT xopername, CAST(xoperdesc AS VARCHAR(20))
    FROM (
          VALUES ('Street', 'SS'), 
                 ('Town', 'TW')                    
         ) AS XOperLU (xopername, xoperdesc)
 ) SELECT T1.COLUMN_NAME as COLUMN_NAME, T1.DATA_TYPE as DATA_TYPE, ISNULL(S1.xoperdesc,'XX') AS Description FROM INFORMATION_SCHEMA.COLUMNS  AS T1 
   LEFT JOIN XOperLU AS S1
      ON S1.xopername = T1.COLUMN_NAME
      WHERE    (TABLE_SCHEMA = 'dbo') AND (TABLE_NAME = 'Clients')

SQL查询内部连接与临时表

1 个答案: