循环存储过程太慢

Question

这里我有一个存储过程似乎比我希望的运行时间更长一些。使这个算法如此冗长的原因是在SQL中将一个元素添加到一个新表时，它似乎并不总是放在最顶层。

我还必须查询创建另一个表的查询。总而言之，这个算法太大了。有没有人想让它变短？

DECLARE @RecipeQuery TABLE(
RecipeID NCHAR(100),
MaterialID NCHAR(100),
Quantity DECIMAL(18,4));

INSERT INTO @RecipeQuery
(RecipeID, MaterialID, Quantity)
SELECT RecipeID, MaterialID, Quantity
FROM Recipe

DECLARE @PrevRecipeQuery TABLE(
prevRecipeID NCHAR(100),
prevMaterialID NCHAR(100),
prevQuantity DECIMAL(18,4));

DECLARE @TempRecipeQuery TABLE(
TempRecipeID NCHAR(100),
TempMaterialID NCHAR(100),
TempQuantity DECIMAL(18,4));

DECLARE @MaterialFinder TABLE(
RID NCHAR(100),
MID NCHAR(100),
Q DECIMAL(18,4));

DECLARE @PrevMaterialFinder TABLE(
PRID NCHAR(100),
PMID NCHAR(100),
PQ DECIMAL(18,4));

DECLARE @CalcMaterial TABLE(
CalcRecipeID NCHAR(100),
CalcMaterialID NCHAR(100),
CalcQuantity DECIMAL(18,4));

DECLARE @ROWCOUNT1 INT
SET @ROWCOUNT1 = 0

DECLARE @ROWCOUNT2 INT
SET @ROWCOUNT2 = 0

DECLARE @ROWCOUNT3 INT 
SET @ROWCOUNT3 = 0

DECLARE @isDone INT
SET @isDone = 0

DECLARE @mainRowCount INT

--------------------------------------------------------------------------------------------------

--LOOP UNTIL ALL LEVELS HAVE BEEN FOUND
WHILE(@isDone != 1)
BEGIN

SET @mainRowCount = (SELECT COUNT(*) FROM @RecipeQuery)

--LOOP THROUGH EACH ROW IN THE TABLE UNTIL ALL ROWS HAVE BEEN LOOKED AT
WHILE(@ROWCOUNT1 < @mainRowCount)
BEGIN

--IF THE ROW'S MATERIAL STARTS WITH A "TempRecipeID" THAT MEANS IT IS DONE
IF(PATINDEX('R%', (SELECT TOP 1 MaterialID FROM @RecipeQuery)) = 1)
BEGIN
--INSERT THE ROW RIGHT INTO TABLE new
    INSERT INTO @CalcMaterial (CalcRecipeID, CalcMaterialID, CalcQuantity) SELECT TOP 1 RecipeID, MaterialID, Quantity FROM @RecipeQuery
    SET @ROWCOUNT3 = @ROWCOUNT3 + 1
END
--OTHERWISE
ELSE
BEGIN
--FIND THE MATERIAL'S RECIPE AND PLACE THE NEW RECIPEID AND MATERIALID INTO TABLE TempMaterialID
    INSERT INTO @PrevMaterialFinder (PRID, PMID, PQ) SELECT TOP(1) RecipeID, MaterialID, Quantity FROM @RecipeQuery
    INSERT INTO @MaterialFinder (RID, MID, Q) SELECT (SELECT TOP 1 RecipeID FROM @RecipeQuery), MaterialID, Quantity FROM Recipe WHERE RecipeID = (SELECT TOP 1 MaterialID FROM @RecipeQuery)

    DECLARE @ROWCOUNT4 INT
    SET @ROWCOUNT4 = (SELECT COUNT(*) FROM @MaterialFinder)
    WHILE(@ROWCOUNT2 < @ROWCOUNT4)
    BEGIN
        INSERT INTO @CalcMaterial
        (CalcRecipeID, CalcMaterialID, CalcQuantity)
        SELECT TOP 1 RID, MID, Q*(SELECT TOP 1 PQ FROM @PrevMaterialFinder)*0.001
        FROM @MaterialFinder

        DELETE TOP(1) FROM @MaterialFinder

        SET @ROWCOUNT2 = @ROWCOUNT2 + 1
    END
    SET @ROWCOUNT2 = 0
END

SET @ROWCOUNT2 = 0

--DELETE THE TOP ROW
DELETE TOP(1)
FROM @RecipeQuery

--INSERT THE UPDATED ROW(S) FROM TABLE TempMaterialID INTO TABLE W
INSERT INTO @TempRecipeQuery
(TempRecipeID, TempMaterialID, TempQuantity)
SELECT CalcRecipeID, CalcMaterialID, CalcQuantity
FROM @CalcMaterial

--DELETE THE UPDATED ROWS FROM TABLE TempMaterialID
DELETE FROM @MaterialFinder
DELETE FROM @PrevMaterialFinder
DELETE FROM @CalcMaterial

--INCREASE ROW COUNTER C
SET @ROWCOUNT1 = @ROWCOUNT1 + 1

--LOOP ONTO NEXT ROW
END
--AT THIS POINT ALL OF THE ROWS HAVE BEEN GONE THROUGH AT LEAST ONCE

--INSERT THE UPDATED ROWS IN TABLE W INTO THE MAIN TABLE 
INSERT INTO @RecipeQuery
(RecipeID, MaterialID, Quantity)
SELECT TempRecipeID, TempMaterialID, TempQuantity
FROM @TempRecipeQuery

--TO COMPARE
--IF THE COUNT OF BOTH TABLES IS THE SAME THEY COULD BE THE SAME
IF((SELECT COUNT(*) FROM @prevRecipeQuery) = (SELECT COUNT(*) FROM @RecipeQuery))
BEGIN
--IF THE DIFFERENCES BETWEEN THE TWO ARE NULL THEN THEY ARE THE SAME;
    IF(SELECT MaterialID FROM @RecipeQuery EXCEPT SELECT prevMaterialID FROM @prevRecipeQuery) IS NULL
--SET DONE TO 1 TO END LOOP
    SET @isDone = 1
END

--DELETE PREV TABLE FOR NEW UPDATE
DELETE FROM @prevRecipeQuery

--SET COPY INTO PREV
INSERT INTO @prevRecipeQuery
(prevRecipeID, prevMaterialID, prevQuantity)
SELECT RecipeID, MaterialID, Quantity
FROM @RecipeQuery

--SET THE ROW COUNTER BACK TO 0
SET @ROWCOUNT1 = 0

--DELETE ALL FROM THE TEMP UPDATED TABLE SO THAT IT CAN BE FILLED WITH UPDATED ROWS IF AGAIN
DELETE FROM @TempRecipeQuery

--AT THIS POINT THE LOOP WILL REPEAT IF THERE ARE ANY MORE STOCK SOLUTIONS AS MATERIALS
END

--AT THIS POINT, ALL LOOPS ARE DONE AND THE MAIN TABLE DOES NOT CONSIST OF ANY STOCK MATERIALS AS MATERIALS
--PRINT THE MAIN TABLE
SELECT RecipeID, MaterialID, Quantity FROM @RecipeQuery
ORDER BY RecipeID

输入是食谱表 输出是输出所需表， 您可以看到添加的行为黄色，因为查询会查询自己以查找每个配方中的材料。

请注意，只有列和第3行必须出现在最终查询中。我添加了这些以显示如何生成3级。

INPUT：
食谱材料

aa01 B1
aa01 B2
aa01 bb01
bb01 B1
bb01 cc01
cc01 B3
cc01 B4
B1 B1
B2 B2
B3 B3
B4 B4

输出：
食谱材料

aa01 B1
aa01 B2
aa01 B1
aa01 B3
aa01 B4
bb01 B1
bb01 B3
bb01 B4
cc01 B3
cc01 B4
B1 B1
B2 B2
B3 B3
B4 B4

Answer 1

我的故事是关于如何改善SP中while循环的性能：

我遇到了同样的问题，即while循环的性能缓慢，几乎有五十万行。我使用表变量循环并使用标识列作为迭代器。太慢了。后来我将table变量更改为本地临时表，并根据循环内的select命令创建了一些索引。从30分钟的早期开始，总时间急剧减少到2-3分钟。 如果您还有那么多行，请尝试使用具有适当索引的临时表。

简而言之：尝试使用具有适当索引的临时表替换表变量。