光标内部的复杂CASE语句的正确语法

Question

我需要我的Cursor中的CASE语句正确的syntx帮助。

背景：我希望CASE语句要做的是查看表Concatenated_File和列FileID中的任何一行说'File1'，我希望它更新相应的表中的MRNID，这是标题Load_File_1。我想继续CASE语句，即任何一行说'File2'，我希望它更新适当的表中的MRNID，Load_File_2。

这是我到目前为止，但我无法弄清楚正确的语法。任何帮助，将不胜感激。谢谢。

DECLARE @FILEID AS VARCHAR(255) 
DECLARE @MRNID AS VARCHAR(255) 
DECLARE @UniqueID AS VARCHAR(255) 
DECLARE @LNAME AS VARCHAR(255) 
DECLARE @FNAME AS VARCHAR(255) 
DECLARE @Birthdate AS VARCHAR(255) 
DECLARE @SSN AS VARCHAR(255) 
DECLARE @HOLD_MRNID AS VARCHAR(255) 
DECLARE @HOLD_UniqueID AS VARCHAR(255) 
DECLARE @HOLD_LNAME AS VARCHAR(255) 
DECLARE @HOLD_FNAME AS VARCHAR(255) 
DECLARE @HOLD_Birthdate AS VARCHAR(255) 
DECLARE @HOLD_SSN AS VARCHAR(255) 

SET NOCOUNT ON 
DECLARE curDB CURSOR FAST_FORWARD FOR 

----------------------------------------------- 
SELECT UniqueID, MRNID, LNAME, FNAME, Birthdate, SSN 
FROM Concatenated_File 
ORDER BY LNAME, FNAME, Birthdate, SSN 
----------------------------------------------- 

-- initialize variables 
select @FILEID='' 
select @MRNID='' 
select @UniqueID='' 
select @FNAME='' 
select @LNAME='' 
select @Birthdate='' 
select @SSN='' 
select @HOLD_MRNID='' 
select @HOLD_UniqueID='' 
select @HOLD_FNAME='' 
select @HOLD_LNAME='' 
select @HOLD_Birthdate='' 
select @HOLD_SSN='' 

OPEN curDB 

FETCH NEXT FROM curDB into @FILEID, @MRNID, @UniqueID, @FNAME, @LNAME, @Birthdate, @SSN 
WHILE (@@FETCH_STATUS = 0) 
    BEGIN 

     IF @LNAME = @HOLD_LNAME and @FNAME = @HOLD_FNAME and @Birthdate = @HOLD_Birthdate and @SSN = @HOLD_SSN 
       BEGIN 

        select @FILEID 
         CASE 
          When @FILEID = 'File1' Then 
          Update Load_File1 
          Set MRNID = @HOLD_MRNID 
          Where UniqueID = @UniqueID 

          When @FILEID = 'File2' Then 
          Update Load_File2 
          Set MRNID = @HOLD_MRNID 
          Where UniqueID = @UniqueID 



       END 
     ELSE 

       BEGIN 
        select @HOLD_UniqueID = @UniqueID 
        select @HOLD_MRNID = @MRNID 
        select @HOLD_FNAME = @FNAME 
        select @HOLD_LNAME = @LNAME 
        select @HOLD_Birthdate = @Birthdate 
        select @HOLD_SSN = @SSN 
       END 
     FETCH NEXT FROM curDB into @FILEID, @MRNID, @UniqueID, @FNAME, @LNAME, @Birthdate, @SSN 
    END 

CLOSE curDB DEALLOCATE curDB

Answer 1

CASE不是控制结构的流量，你需要IF

IF @FILEID = 'File1' 
    UPDATE Load_File1 
    SET MRNID = @HOLD_MRNID 
    WHERE UniqueID = @UniqueID 
ELSE IF @FILEID = 'File2' 
    UPDATE Load_File2 
    SET MRNID = @HOLD_MRNID 
    WHERE UniqueID = @UniqueID 

我不知道到底是什么光标更新逻辑在做什么。一般来说，你最好使用基于集合的技术。