Question

首先让我解释一下我不太使用SQL。

我正在使用其他人的代码，因此需要通过在WHERE子句中将零打折掉来减少返回的行数。但是我不确定该怎么做，因为我要折扣的商品是计算='openquantity'的结果

SELECT
    stockallocations.partid,
    stockallocations.quantity - issuedquantity as openquantity,
    (CASE   
        WHEN stockallocations.source = 'SO' THEN stockallocations.reference
        WHEN stockallocations.source = 'KIT' THEN stockallocations.worksorderid
        ELSE 'Manual'
    END) as source,
    (CASE   
        WHEN stockallocations.source = 'SO' THEN salesorderitems.duedate
        WHEN stockallocations.source = 'KIT' THEN worksorders.lateststartdate
        ELSE 'createddate'
    END) as needed
FROM
    stockallocations
    LEFT OUTER JOIN salesorderitems ON
    stockallocations.orderid = salesorderitems.orderid AND
    stockallocations.orderitemnumber = salesorderitems.itemnumber
    LEFT OUTER JOIN worksorders ON
    stockallocations.worksorderid = worksorders.id

WHERE
    stockallocations.partid = 'ABC123'
    --and openquantity > 0 (this doesn't work).

任何建议都将受到欢迎。

谢谢标记

Answer 1

尝试使用and (stockallocations.quantity - issuedquantity) > 0代替and openquantity > 0。别名在where子句中无效。

Answer 2

我不确定SQL是否允许您在WHERE子句中使用别名。

尝试以下方法：

WHERE
    stockallocations.partid = 'ABC123'
AND stockallocations.quantity - issuedquantity > 0

谢谢， Dom

Answer 3

您不能在WHERE子句中使用别名。而是使用

SELECT * from (SELECT ...) WHERE openquantity > 0

或

WITH SEL1 as (SELECT ...)
SELECT * from SEL1 where openquantity > 0

或者如果计算是如此简单，只需将其复制：

SELECT ...
WHERE stockallocations.partid = 'ABC123'
AND stockallocations.quantity - issuedquantity > 0

请注意，前两个选项可能不适用于每个数据库。

Answer 4

首先，我将使用表别名编写查询，并在WHERE子句中解决列别名问题：

SELECT sa.partid, (sa.quantity - issuedquantity) as openquantity,
       (CASE WHEN sa.source = 'SO' THEN sa.reference
             WHEN sa.source = 'KIT' THEN sa.worksorderid
             ELSE 'Manual'
        END) as source,
       (CASE  WHEN sa.source = 'SO' THEN soi.duedate
              WHEN sa.source = 'KIT' THEN wo.lateststartdate
             ELSE 'createddate'
        END) as needed
FROM stockallocations sa LEFT JOIN
     salesorderitems soi ON
     ON sa.orderid = soi.orderid AND
        sa.orderitemnumber = soi.itemnumber LEFT JOIN
     worksorders wo ON
     ON sa.worksorderid = wo.id
WHERE sa.partid = 'ABC123' AND
      sa.quantity > issuedquantity;

接下来，大概issuedquantity来自stockallocations。如果不是，则WHERE子句将一个或多个LEFT JOIN变成INNER JOIN。

最后，CASE表达式可疑。 ELSE子句返回字符串，但是sa.worksorderid可能是数字，并且日期看起来像日期。在单个表达式中混合这样的类型时，通常会遇到类型转换错误。

SQL查询仅返回值> 0的项目

4 个答案: