Using row count from a temporary table in a while loop SQL Server 2008

问题

I'm trying to create a procedure in SQL Server 2008 that inserts data from a temp table into an already existing table. I think I've pretty much figured it out, I'm just having an issue with a loop. I need the row count from the temp table to determine when the loop should finish.

I've tried using @@ROWCOUNT in two different ways; using it by itself in the WHILE statement, and creating a variable to try and hold the value when the first loop has finished (see code below).

Neither of these methods have worked, and I'm now at a loss as to what to do. Is it possible to use @@ROWCOUNT in this situation, or is there another method that would work better?

CREATE PROCEDURE InsertData(@KeywordList varchar(max))
AS
BEGIN

--create temp table to hold words and weights
CREATE TABLE #tempKeywords(ID int NOT NULL, keyword varchar(10) NOT NULL); 

DECLARE @K varchar(10), @Num int, @ID int

SET @KeywordList= LTRIM(RTRIM(@KeywordList))+ ','
SET @Num = CHARINDEX(',', @KeywordList, 1)
SET @ID = 0

--Parse varchar and split IDs by comma into temp table
IF REPLACE(@KeywordList, ',', '') <> ''
BEGIN
    WHILE @Num > 0
    BEGIN
        SET @K= LTRIM(RTRIM(LEFT(@KeywordList, @Num - 1)))
        SET @ID = @ID + 1
        IF @K <> ''
        BEGIN
            INSERT INTO #tempKeywords VALUES (@ID, @K) 
        END
        SET @KeywordList = RIGHT(@KeywordList, LEN(@KeywordList) - @Num)
        SET @Num = CHARINDEX(',', @KeywordList, 1)
        --rowcount of temp table
        SET @rowcount = @@ROWCOUNT
    END
END

--declaring variables for loop
DECLARE @count INT
DECLARE @t_name varchar(30)
DECLARE @key varchar(30)
DECLARE @key_weight DECIMAL(18,2)
--setting count to start from first keyword
SET @count = 2
--setting the topic name as the first row in temp table
SET @t_name = (Select keyword from #tempKeywords where ID = 1)
--loop to insert data from temp table into Keyword table
WHILE(@count < @rowcount)
    BEGIN
        SET @key = (SELECT keyword FROM #tempKeywords where ID = @count)
        SET @key_weight = (SELECT keyword FROM #tempKeywords where ID = @count+2)
        INSERT INTO Keyword(Topic_Name,Keyword,K_Weight)
        VALUES(@t_name,@key,@key_weight)
        SET @count= @count +2
    END 
--End stored procedure  
END

回答1:

To solve the second part of your problem:

INSERT INTO Keyword(Topic_Name,Keyword,K_Weight)
SELECT tk1.keyword, tk2.keyword, tk3.keyword
FROM
    #tempKeywords tk1
        cross join
    #tempKeywords tk2
        inner join
    #tempKeywords tk3
        on
           tk2.ID = tk3.ID - 1
WHERE
    tk1.ID = 1 AND
    tk2.ID % 2 = 0

(This code should replace everything in your current script from the --declaring variables for loop comment onwards)

回答2:

You could change:

WHILE(@count < @rowcount)

WHILE(@count < (select count(*) from #tempKeywords))

But like marc_s commented, you should be able to do this without a while loop.

回答3:

I'd look at reworking your query to see if you can do this in a set based way rather than row by row.

I'm not sure I follow exactly what you are trying to achieve, but I'd be tempted to look at the ROW_NUMBER() function to set the ID of your temp table. Used with a recursive CTE such as shown in this answer you could get an id for each of your non empty trimmed words. An example is something like;

DECLARE @KeywordList varchar(max) = 'TEST,WORD, ,,,LIST, SOME , WITH, SPACES'

CREATE TABLE #tempKeywords(ID int NOT NULL, keyword varchar(10) NOT NULL) 

;WITH kws (ord, DataItem, Data) AS(
    SELECT CAST(1 AS INT), LEFT(@KeywordList, CHARINDEX(',',@KeywordList+',')-1) ,
    STUFF(@KeywordList, 1, CHARINDEX(',',@KeywordList+','), '') 
    union all
    select ord + 1, LEFT(Data, CHARINDEX(',',Data+',')-1),
        STUFF(Data, 1, CHARINDEX(',',Data+','), '')
        from kws
        where Data > ''
), trimKws(ord1, trimkw) AS (
    SELECT ord, RTRIM(LTRIM(DataItem)) 
    FROM kws
) 
INSERT INTO #tempKeywords (ID, keyword) 
SELECT ROW_NUMBER() OVER (ORDER BY ord1) as OrderedWithoutSpaces, trimkw 
FROM trimKws WHERE trimkw <> '' 

SELECT * FROM #tempKeywords

I don't fully understand what you are trying to acheive with the second part of your query , but but you could just build on this to get the remainder of it working. It certainly looks as though you could do what you are after without while statements at least.

来源：https://stackoverflow.com/questions/12833787/using-row-count-from-a-temporary-table-in-a-while-loop-sql-server-2008

标签

sql-server

sql-server-2008

while-loop

temp-tables

rowcount