Mysql 查找公共属性的SQL查询
我有一个由ERP生成的带有3列的SQL表Mysql 查找公共属性的SQL查询,mysql,sql,sql-server,Mysql,Sql,Sql Server,我有一个由ERP生成的带有3列的SQL表 +-----------+-----------+------------+ | ProductID | Attribute | Value | +-----------+-----------+------------+ | 100 | Size | Big | | 100 | Color | Red | | 100 | Weight | Heavy
+-----------+-----------+------------+
| ProductID | Attribute | Value |
+-----------+-----------+------------+
| 100 | Size | Big |
| 100 | Color | Red |
| 100 | Weight | Heavy |
| 200 | Size | Small |
| 200 | Color | Red |
| 200 | Weight | Light |
| 300 | Size | Big |
| 300 | Color | Green |
| 300 | Weight | Heavy |
+-----------+-----------+------------+
我想查询表以查找具有匹配属性的产品。比如说
SELECT * FROM Table
WHERE Attribute ='Size' AND Value = 'Big' AND Attribute ='Weight' AND Value = 'Heavy'
所以退回产品100和300。有两种不同的方法可以做到这一点。下面是一个使用条件聚合的示例:
select productid
from yourtable
group by productid
having max(case when attribute = 'Size' then value end) = 'Big'
and max(case when attribute = 'Weight' then value end) = 'Heavy'
和来执行此操作:
SELECT ProductID
FROM tbl
GROUP BY ProductID
HAVING
SUM(
CASE
WHEN Attribute = 'Size' AND Value = 'BIG' THEN 1
WHEN Attribute = 'Weight' AND Value = 'Heavy' THEN 1
ELSE 0
END
) = 2
如果您希望ProductID
s具有其他属性,可以使用=2
。我相信您需要成对的产品。此外,我没有在任何地方硬编码值。如果需要更改属性集,只需修改having
子句
select t1.ProductID, t2.ProductID
from
T t1 inner join T t2
on t2.ProductID > t1.ProductID
and t2.Attribute = t1.Attribute and t2.Value = t1.Value
group by
t1.ProductID, t2.ProductID
having
count(case when t1.Attribute = 'Size' then 1 end) = 1
and count(case when t1.Attribute = 'Weight' then 1 end) = 1
我有点倾向于认为像Felix这样的答案就是你想要的。另一种方法是使用传统的“透视查询”并将其视为“派生表”,然后将大小/重量/颜色作为行,从而简化筛选
MySQL 5.6架构设置:
CREATE TABLE ERPout
(`ProductID` int, `Attribute` varchar(6), `Value` varchar(5))
;
INSERT INTO ERPout
(`ProductID`, `Attribute`, `Value`)
VALUES
(100, 'Size', 'Big'),
(100, 'Color', 'Red'),
(100, 'Weight', 'Heavy'),
(200, 'Size', 'Small'),
(200, 'Color', 'Red'),
(200, 'Weight', 'Light'),
(300, 'Size', 'Big'),
(300, 'Color', 'Green'),
(300, 'Weight', 'Heavy')
;
SELECT
ProductID
, Size
, Color
, Weight
FROM (
SELECT
ProductID
, MAX(CASE WHEN Attribute = 'Size' THEN VALUE END) AS Size
, MAX(CASE WHEN Attribute = 'Color' THEN VALUE END) AS Color
, MAX(CASE WHEN Attribute = 'Weight' THEN VALUE END) AS Weight
FROM ERPout
GROUP BY
ProductID
) p
WHERE Size = 'Big'
AND Weight = 'Heavy'
| ProductID | Size | Color | Weight |
|-----------|------|-------|--------|
| 100 | Big | Red | Heavy |
| 300 | Big | Green | Heavy |
查询1:
CREATE TABLE ERPout
(`ProductID` int, `Attribute` varchar(6), `Value` varchar(5))
;
INSERT INTO ERPout
(`ProductID`, `Attribute`, `Value`)
VALUES
(100, 'Size', 'Big'),
(100, 'Color', 'Red'),
(100, 'Weight', 'Heavy'),
(200, 'Size', 'Small'),
(200, 'Color', 'Red'),
(200, 'Weight', 'Light'),
(300, 'Size', 'Big'),
(300, 'Color', 'Green'),
(300, 'Weight', 'Heavy')
;
SELECT
ProductID
, Size
, Color
, Weight
FROM (
SELECT
ProductID
, MAX(CASE WHEN Attribute = 'Size' THEN VALUE END) AS Size
, MAX(CASE WHEN Attribute = 'Color' THEN VALUE END) AS Color
, MAX(CASE WHEN Attribute = 'Weight' THEN VALUE END) AS Weight
FROM ERPout
GROUP BY
ProductID
) p
WHERE Size = 'Big'
AND Weight = 'Heavy'
| ProductID | Size | Color | Weight |
|-----------|------|-------|--------|
| 100 | Big | Red | Heavy |
| 300 | Big | Green | Heavy |
:
CREATE TABLE ERPout
(`ProductID` int, `Attribute` varchar(6), `Value` varchar(5))
;
INSERT INTO ERPout
(`ProductID`, `Attribute`, `Value`)
VALUES
(100, 'Size', 'Big'),
(100, 'Color', 'Red'),
(100, 'Weight', 'Heavy'),
(200, 'Size', 'Small'),
(200, 'Color', 'Red'),
(200, 'Weight', 'Light'),
(300, 'Size', 'Big'),
(300, 'Color', 'Green'),
(300, 'Weight', 'Heavy')
;
SELECT
ProductID
, Size
, Color
, Weight
FROM (
SELECT
ProductID
, MAX(CASE WHEN Attribute = 'Size' THEN VALUE END) AS Size
, MAX(CASE WHEN Attribute = 'Color' THEN VALUE END) AS Color
, MAX(CASE WHEN Attribute = 'Weight' THEN VALUE END) AS Weight
FROM ERPout
GROUP BY
ProductID
) p
WHERE Size = 'Big'
AND Weight = 'Heavy'
| ProductID | Size | Color | Weight |
|-----------|------|-------|--------|
| 100 | Big | Red | Heavy |
| 300 | Big | Green | Heavy |
如果您只需要ProductID,这将是一个简短而有效的解决方案:
选择ProductID
从产品信息
其中Attribute='Size'和Value='Big'
或属性='Weight'和值='Heavy'
按产品ID分组
拥有计数(ProductID)=2
如果您需要一行中的所有属性,并且您已经在(ProductID,Attribute)上定义了(唯一/主)键,那么您可能希望使用如下查询:
选择size.ProductID、size.Value-size、color.Value-color、weight.Value-weight
从产品信息大小
使用(ProductID)加入产品信息权重
左连接产品信息颜色
关于color.ProductID=size.ProductID
属性='color'
其中size.Attribute='size'和size.Value='Big'
和weight.Attribute='weight'和weight.Value='Heavy'
如果您另外定义一个基于值的索引,那么性能会更好
这两个查询都使用WHERE子句,避免了完整的表/索引扫描。根据表大小和数据,这可能是一个巨大的优势,因为早期筛选。您没有解释“查找具有匹配属性的产品”的含义:输入是什么?只是那个表,或者其他一些,或者一些参数/常量?当你询问时,为什么要询问?所需的查询应该是什么样子的?就输入而言,输出应该是什么样的?请给出输入和输出示例。PS为什么有两个不同的DBMS标记?MySQL和/或MS SQL Server?(不要给未涉及的产品贴标签…)哥们,这样效果更好。非常感谢,伙计。你是个救生员。