Question

我有一些PLSQL代码循环一些逻辑：

 FOR I in cur1
 LOOP

    SELECT value1, value2
    FROM db1..table1 t1

 END LOOP;

任何人都可以向我解释在TSQL中执行此操作的语法吗？

Answer 1

这是标准TSQL游标中的通用循环。但尽可能避免使用游标。他们的表现非常糟糕。

DECLARE @somevariable VARIABLE_TYPE_HERE
DECLARE @sampleCursor CURSOR

SET @sampleCursor = CURSOR FOR
SELECT somefield... from bla bla bla...

OPEN @sampleCursor 
FETCH NEXT
FROM @sampleCursor INTO @somevariable 
WHILE @@FETCH_STATUS = 0
BEGIN

PRINT @somevariable 

FETCH NEXT
FROM @sampleCursor INTO @somevariable 

END
CLOSE @sampleCursor 
DEALLOCATE @sampleCursor

Answer 2

T-SQL中没有FOR。 WHILE的一个例子：

DECLARE Employee_Cursor CURSOR FOR
SELECT EmployeeID, Title 
FROM AdventureWorks2008R2.HumanResources.Employee

OPEN Employee_Cursor;

FETCH NEXT FROM Employee_Cursor;

WHILE @@FETCH_STATUS = 0
BEGIN
   FETCH NEXT FROM Employee_Cursor;
END;

CLOSE Employee_Cursor;

DEALLOCATE Employee_Cursor;

有关详细信息：http://msdn.microsoft.com/en-us/library/ms178642.aspx

将PL SQL游标FOR循环语法转换为SQL

2 个答案: