Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
282 views
in Technique[技术] by (71.8m points)

sql server - Can I loop through a table variable in T-SQL?

Is there anyway to loop through a table variable in T-SQL?

DECLARE @table1 TABLE ( col1 int )  
INSERT into @table1 SELECT col1 FROM table2

I use cursors as well, but cursors seem less flexible than table variables.

DECLARE cursor1 CURSOR  
    FOR SELECT col1 FROM table2  
OPEN cursor1  
FETCH NEXT FROM cursor1

I would like to be able to use a table variable in the same manner as a cursor. That way I could execute some query on the table variable in one part of the procedure, and then later execute some code for each row in the table variable.

Any help is greatly appreciated.

See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Reply

0 votes
by (71.8m points)

Add an identity to your table variable, and do an easy loop from 1 to the @@ROWCOUNT of the INSERT-SELECT.

Try this:

DECLARE @RowsToProcess  int
DECLARE @CurrentRow     int
DECLARE @SelectCol1     int

DECLARE @table1 TABLE (RowID int not null primary key identity(1,1), col1 int )  
INSERT into @table1 (col1) SELECT col1 FROM table2
SET @RowsToProcess=@@ROWCOUNT

SET @CurrentRow=0
WHILE @CurrentRow<@RowsToProcess
BEGIN
    SET @CurrentRow=@CurrentRow+1
    SELECT 
        @SelectCol1=col1
        FROM @table1
        WHERE RowID=@CurrentRow

    --do your thing here--

END

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
OGeek|极客中国-欢迎来到极客的世界,一个免费开放的程序员编程交流平台!开放,进步,分享!让技术改变生活,让极客改变未来! Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...