T-SQL从测试动态迁移到生产（第2部分）

好吧，自从我上一次，我能够取得进步！！然而，我又遇到了另一个问题……再一次：

目标：传入两个参数（任务和主键）以生成表列表。获取列表，然后动态构造insert语句，目的是将数据从生产环境复制到测试环境。换句话说，以编程方式完成“编辑前200名”的工作……但速度要快得多

问题（已更新）：@tmpInserVars没有在每次迭代中更新。它在第一次输入代码时设置，并且从不刷新

迄今为止：

USE MAINDB
DECLARE @PK int = 1000,
 @TaskName nvarchar(50) = 'TASK', 
 @curTable nvarchar(75),
 @curRow nvarchar(75),
 @tmpStatement nvarchar(500),
 @tmpInsert nvarchar(500)

RAISERROR('Retrieving Tables',0,1) WITH NOWAIT
 DECLARE TableCursor CURSOR LOCAL FOR 

    SELECT DISTINCT TOP 2 PRMPTTBL.tTable as PromptTable
       FROM THING1 TK INNER JOIN THING2 SC ON TK.tkNo=SC.tkNo
              INNER JOIN Component EL on EL.scNo=SC.scNo             
              LEFT OUTER JOIN Field FLD1 on FLD1.cfNo=EL.cfNoPrompt1            
              LEFT OUTER JOIN MyTableTable MTTTBL on MTTTBL.tbNo=FLD1.tbNo

       WHERE EL.PK=@PK
              AND (MTTTBL.tTable is not NULL AND MTTTBL.tTable not in('OneTableIDontWant'))
              AND MTTTBL.tTable not like '%[_]d%' --eliminate any tables that are actually views
              AND EL.cfNo > 0  
              AND TK.Description like @TaskName

RAISERROR('Table',0,1) WITH NOWAIT
OPEN TableCursor
FETCH NEXT FROM TableCursor INTO @curTable
WHILE @@FETCH_STATUS = 0
BEGIN
   SET @tmpStatement = 'SELECT TOP 5 * FROM [MYCONN].TEST_MYDB.dbo.' + @curTable + ' where PK=' + Cast(@PK as nvarchar(10))
   EXEC (@tmpStatement)
   RAISERROR(N'Table (outside): %s',0,1,@curTable) WITH NOWAIT  

   IF @@ROWCOUNT = 0 
   BEGIN
        --@tmpInsertVars isn't updating!!!
        RAISERROR(N'Initial Select: %s',0,1,@tmpStatement) WITH NOWAIT
        SELECT @tmpInsertVars = COALESCE(@tmpInsertVars + ',','') + COLUMN_NAME 
        FROM PRODDB.INFORMATION_SCHEMA.COLUMNS
        WHERE TABLE_NAME = @curTable

        SET @tmpInsertStatement = 'INSERT INTO [MYCONN].TEST_MYDB.dbo.' + @curTable + ' (' + @tmpInsertVars + ')' +
                                  ' SELECT TOP 500 ' + @tmpInsertVars +
                                  ' FROM TEST_MYDB.' + @curTable +
                                  ' WHERE PK=' + Cast(@PK as nvarchar(10))

        RAISERROR(N'Insert Statement: %s',0,1,@tmpInsertStatement) WITH NOWAIT
   END


   FETCH NEXT FROM TableCursor INTO @curTable
END

CLOSE TableCursor
DEALLOCATE TableCursor

声明@tmpInsertStatement和@tmpInsertVars变量

在填充@tmpInsertVars之前将其重置为NULL

USE MAINDB
DECLARE @PK int = 1000,
 @TaskName nvarchar(50) = 'TASK', 
 @curTable nvarchar(75),
 @curRow nvarchar(75),
 @tmpStatement nvarchar(500),
 @tmpInsert nvarchar(500),
 @tmpInsertStatement nvarchar(500),
 @tmpInsertVars nvarchar(500)

RAISERROR('Retrieving Tables',0,1) WITH NOWAIT
 DECLARE TableCursor CURSOR LOCAL FOR 

    SELECT DISTINCT TOP 2 PRMPTTBL.tTable as PromptTable
       FROM THING1 TK INNER JOIN THING2 SC ON TK.tkNo=SC.tkNo
              INNER JOIN Component EL on EL.scNo=SC.scNo             
              LEFT OUTER JOIN Field FLD1 on FLD1.cfNo=EL.cfNoPrompt1            
              LEFT OUTER JOIN MyTableTable MTTTBL on MTTTBL.tbNo=FLD1.tbNo

       WHERE EL.PK=@PK
              AND (MTTTBL.tTable is not NULL AND MTTTBL.tTable not in('OneTableIDontWant'))
              AND MTTTBL.tTable not like '%[_]d%' --eliminate any tables that are actually views
              AND EL.cfNo > 0  
              AND TK.Description like @TaskName

RAISERROR('Table',0,1) WITH NOWAIT
OPEN TableCursor
FETCH NEXT FROM TableCursor INTO @curTable
WHILE @@FETCH_STATUS = 0
BEGIN
   SET @tmpStatement = 'SELECT TOP 5 * FROM [MYCONN].TEST_MYDB.dbo.' + @curTable + ' where PK=' + Cast(@PK as nvarchar(10))
   EXEC (@tmpStatement)
   RAISERROR(N'Table (outside): %s',0,1,@curTable) WITH NOWAIT  

   IF @@ROWCOUNT = 0 
   BEGIN
        --@tmpInsertVars isn't updating!!!
        SELECT @tmpInsertVars = NULL; -- RESET @tmpInsertVars
        RAISERROR(N'Initial Select: %s',0,1,@tmpStatement) WITH NOWAIT
        SELECT @tmpInsertVars = COALESCE(@tmpInsertVars + ',','') + COLUMN_NAME 
        FROM PRODDB.INFORMATION_SCHEMA.COLUMNS
        WHERE TABLE_NAME = @curTable

        SET @tmpInsertStatement = 'INSERT INTO [MYCONN].TEST_MYDB.dbo.' + @curTable + ' (' + @tmpInsertVars + ')' +
                                  ' SELECT TOP 500 ' + @tmpInsertVars +
                                  ' FROM TEST_MYDB.' + @curTable +
                                  ' WHERE PK=' + Cast(@PK as nvarchar(10))

        RAISERROR(N'Insert Statement: %s',0,1,@tmpInsertStatement) WITH NOWAIT
   END


   FETCH NEXT FROM TableCursor INTO @curTable
END

CLOSE TableCursor
DEALLOCATE TableCursor

---

哇！非常感谢你！！你介意告诉我为什么这样做吗？对我来说，我认为“SELECT@tmpInsertVars=COALESCE（---）”是在每次迭代时重新分配值，但情况显然不是这样。tmpInsertVars变量将继续在后续循环中保留其值，因为赋值语句只是附加到它。COALESCE只接受在其参数中找到的第一个非空值。在每个后续循环中，它仍然具有上一次迭代中的非null值，因此COALESCE语句中的第一个参数将起作用，以保留现有数据并开始追加更多数据。通过在合并之前将tmpInsertVars重置回NULL，您可以确保第一个参数/表达式将为NULL，因为（NULL+，'）=NULL。很好的解释！非常感谢。