sql - 将两个 SQL 查询合并为一个查询的最佳方法

Question

我有两个小的 SQL 查询，我想将它们合并为一个查询，最终将在存储过程中使用。我已经尝试过 CASE 和 IF/ELSE 但无法让它工作。下面是代码。我想要实现的是，第一列“未结订单行数”基于两个查询中的两个 where 语句，但第二列“总数量”仅基于第二个查询中的 where 语句。

select 
COUNT(OO.ORNO) AS 'Count of Open Order Lines'
from OOLINE OO
    join OOHEAD OH
    on OO.CONO = OH.CONO
    and OO.ORNO = OH.ORNO
where OO.ORST BETWEEN 22 AND 66
    and OH.OBLC BETWEEN 1 AND 8;


select 
CAST(SUM(OO.ORQT) AS DECIMAL (8,0)) AS 'Sum Quantity'
from OOLINE OO
    join OOHEAD OH
    on OO.CONO = OH.CONO
    and OO.ORNO = OH.ORNO
where OO.ORST BETWEEN 22 AND 66;

Answer 1

您需要条件聚合：

SELECT COUNT(CASE WHEN OH.OBLC BETWEEN 1 AND 8 THEN OO.ORNO END) AS "Count_of_Open_Order_Lines",
       CAST(SUM(OO.ORQT) AS DECIMAL (8,0)) AS Sum_Quantity
FROM OOLINE OO INNER JOIN OOHEAD OH
ON OO.CONO = OH.CONO AND OO.ORNO = OH.ORNO
WHERE OO.ORST BETWEEN 22 AND 66;

在WHERE子句中，我只保留了OO.ORST BETWEEN 22 AND 66两个查询中通用的条件，并且Count of Open Order Lines我使用了CASE基于条件的表达式OH.OBLC BETWEEN 1 AND 8。