如何這個動態查詢轉換爲普通的SQL查詢

Question

如何這個動態查詢轉換爲普通的SQL查詢

SET @SQL = 'SELECT DelayId, DelayCategory, DelayReason FROM [TAMS].[DelayMaintenance] WHERE IsUtilized = 1 AND ' + @CHECKPOINTTYPE + ' = ' + CAST(1 AS CHAR(1)) + 
     ' union  SELECT 0, NULL, ''--- Pick One----'' ORDER BY DelayId' 

EXEC (@SQL) 

Answer 1

假設有潛在列名的數量有限，你可以這樣做：

SELECT * 
from MyTable 
where CASE @CHECKPOINTTYPE 
    WHEN 'Column1' THEN Column1 
    WHEN 'Column2' THEN Column2 
    ELSE NULL 
    END = 1 

否則，您可以在傳遞到SQL Server之前使用服務器端語言構建查詢，這與您已經使用的解決方案几乎完全相同。

Answer 2

我已經試過這

SELECT DelayId, DelayCategory, DelayReason 
    FROM [TAMS].[DelayMaintenance] 
    WHERE CASE @CHECKPOINTTYPE 
     WHEN 'TRUCK' THEN Truck 
     WHEN 'RAIL' THEN RAIL 
     WHEN 'BARGE' THEN BARGE 
     ELSE NULL 
     END = 1 
     AND IsUtilized = 1 
    union  SELECT 0, NULL, '--- Pick One----' ORDER BY DelayId