SELECTサブクエリ内のIF/CASE文

Question

私のスクリプトはほぼ完全に動作しますが、以下の部分だけが問題を引き起こしています。コードのこの部分はFSFSRテーブルにレコードが存在する場合には完璧に動作しますが、行が存在しない場合は、SCFSRテーブル+1のMAX値ではなくになります。作業。以下

(SELECT MAX(SCFSR.FSR_Num) FROM SCFSR WHERE SCFSR.FSR_Call_Num = T_Call_Num)+1 

全コード：

BEGIN TRY 
BEGIN TRANSACTION 
USE Tesseracttestv5 

--------- DELCARE ARRAY --------- 

DECLARE @RANGE TABLE(T_Call_Num INT); 

INSERT @RANGE(T_Call_Num) VALUES (441925),(429021),(393852); 

--------- SET CALL TO COMP --------- 

UPDATE SCCall 
SET 
Call_Status = 'COMP', 
Call_CDate = GETDATE() 
WHERE Call_Num IN (SELECT T_Call_Num FROM @RANGE) 

--------- INSERT SERVICE REPORT --------- 

INSERT INTO SCFSR (FSR_Call_Num, FSR_Call_Status, FSR_Start_Date,  FSR_Complete_Date, FSR_Last_Update, 
        FSR_Symp_Code, FSR_Fault_Code,  FSR_Rep_Code,  FSR_Solution,  FSR_User, 
        FSR_Num,   FSR_Cost_Centre, FSR_Site_Num,  FSR_Area_Code,  FSR_Employ_Num, 
        FSR_Prod_Num) 

SELECT  T_Call_Num, 
      'COMP', GETDATE(), GETDATE(), GETDATE(), 'GEN', 'OPN', 0, 'Closed as part of database cleanse', 'JTY', 
      (SELECT MAX(SCFSR.FSR_Num) FROM SCFSR WHERE SCFSR.FSR_Call_Num = T_Call_Num)+1,    
      (SELECT SCCall.Call_Cont_Num FROM SCCall WHERE SCCall.Call_Num = T_Call_Num), 
      (SELECT SCCall.Call_Site_Num FROM SCCall WHERE SCCall.Call_Num = T_Call_Num), 
      (SELECT SCCall.Call_Area_Code FROM SCCall WHERE SCCall.Call_Num = T_Call_Num), 
      (SELECT SCCall.Call_Employ_Num FROM SCCall WHERE SCCall.Call_Num = T_Call_Num), 
      (SELECT SCCall.Call_Prod_Num FROM SCCall WHERE SCCall.Call_Num = T_Call_Num)   
FROM @RANGE 

COMMIT TRANSACTION 
END TRY 

BEGIN CATCH 
IF @@TRANCOUNT > 0 
ROLLBACK TRANSACTION 

SELECT ERROR_NUMBER() AS ErrorNumber, 
     ERROR_MESSAGE() AS ErrorMessage, 
     ERROR_SEVERITY() AS ErrorSeverity, 
     ERROR_LINE() AS ErrorLine 
END CATCH 

Answer 1

使用COALESCE：

COALESCE((SELECT MAX(SCFSR.FSR_Num) FROM SCFSR WHERE SCFSR.FSR_Call_Num = T_Call_Num)+1, 1) 

レコードが存在しない場合、テーブルに存在していたこのサブクエリはあなたにnullを取得し、COALESCEは、最初に戻りますパラメータリスト内のnull以外の要素レコードが存在しないときは、ここで1を返します。