如何合并两个sql查询？

发布于 2024-08-29 01:24:27 字数 1029 浏览 7 评论 0原文

我有一个库存表，我想创建一个报告来显示订购商品的频率。

“stock”表：

item_id |  pcs | operation
apples  |  100 | order
oranges |   50 | order
apples  | -100 | delivery
pears   |  100 | order
oranges |  -40 | delivery
apples  |   50 | order
apples  |   50 | delivery

基本上我需要将这两个查询连接在一起。

打印库存余额的查询：

SELECT stock.item_id, Sum(stock.pcs) AS stock_balance
FROM stock
GROUP BY stock.item_id;

打印销售统计信息的查询

SELECT stock.item_id, Sum(stock.pcs) AS pcs_ordered, Count(stock.item_id) AS number_of_orders
FROM stock
GROUP BY stock.item_id, stock.operation
HAVING stock.operation="order";

我认为某种 JOIN 可以完成这项工作，但我不知道如何将查询粘合在一起。

所需的输出：

item_id | stock_balance | pcs_ordered | number_of_orders
apples  |             0 |         150 |                2
oranges |            10 |          50 |                1
pears   |           100 |         100 |                1

这只是示例。也许，我需要添加更多条件，因为有更多列。是否存在将多个查询组合在一起的通用技术？

原文

I have a stock table and I would like to create a report that will show how often were items ordered.

"stock" table:

item_id |  pcs | operation
apples  |  100 | order
oranges |   50 | order
apples  | -100 | delivery
pears   |  100 | order
oranges |  -40 | delivery
apples  |   50 | order
apples  |   50 | delivery

Basically I need to join these two queries together.

A query which prints stock balances:

SELECT stock.item_id, Sum(stock.pcs) AS stock_balance
FROM stock
GROUP BY stock.item_id;

A query which prints sales statistics

SELECT stock.item_id, Sum(stock.pcs) AS pcs_ordered, Count(stock.item_id) AS number_of_orders
FROM stock
GROUP BY stock.item_id, stock.operation
HAVING stock.operation="order";

I think that some sort of JOIN would do the job but I have no idea how to glue queries together.

Desired output:

item_id | stock_balance | pcs_ordered | number_of_orders
apples  |             0 |         150 |                2
oranges |            10 |          50 |                1
pears   |           100 |         100 |                1

This is just example. Maybe, I will need to add more conditions because there is more columns. Is there a universal technique of combining multiple queries together?

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南风几经秋 2024-09-05 01:24:27

SELECT a.item_id, a.stock_balance, b.pcs_ordered, b.number_of_orders
FROM
    (SELECT stock.item_id, Sum(stock.pcs) AS stock_balance 
    FROM stock 
    GROUP BY stock.item_id) a
LEFT OUTER JOIN
    (SELECT stock.item_id, Sum(stock.pcs) AS pcs_ordered, 
            Count(stock.item_id) AS number_of_orders 
    FROM stock
    WHERE stock.operation = "order"
    GROUP BY stock.item_id) b
ON a.item_id = b.item_id

SELECT a.item_id, a.stock_balance, b.pcs_ordered, b.number_of_orders
FROM
    (SELECT stock.item_id, Sum(stock.pcs) AS stock_balance 
    FROM stock 
    GROUP BY stock.item_id) a
LEFT OUTER JOIN
    (SELECT stock.item_id, Sum(stock.pcs) AS pcs_ordered, 
            Count(stock.item_id) AS number_of_orders 
    FROM stock
    WHERE stock.operation = "order"
    GROUP BY stock.item_id) b
ON a.item_id = b.item_id

回复收藏 0 原文

晨光如昨 2024-09-05 01:24:27

这应该可以做到

SELECT
    stock.item_id, 
    Sum(stock.pcs) AS stock_balance,
    pcs_ordered,
    number_of_orders
FROM stock LEFT OUTER JOIN (
    SELECT stock.item_id,
    SUM(stock.pcs) AS pcs_ordered,
    COUNT(stock.item_id) AS number_of_orders
    FROM stock
    WHERE stock.operation ='order'
    GROUP BY stock.item_id
    ) s2 ON stock.item_id = s2.item_id
GROUP BY 
    stock.item_id,
    pcs_ordered,
    number_of_orders

This should do it

SELECT
    stock.item_id, 
    Sum(stock.pcs) AS stock_balance,
    pcs_ordered,
    number_of_orders
FROM stock LEFT OUTER JOIN (
    SELECT stock.item_id,
    SUM(stock.pcs) AS pcs_ordered,
    COUNT(stock.item_id) AS number_of_orders
    FROM stock
    WHERE stock.operation ='order'
    GROUP BY stock.item_id
    ) s2 ON stock.item_id = s2.item_id
GROUP BY 
    stock.item_id,
    pcs_ordered,
    number_of_orders

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~没有更多了~