按行中的值重复结果行多次 [英] Repeat a result row multiple times by value in row

问题描述

我对sql查询有疑问. 我想复制一个具有相同值的行， 行数必须与数量值相同

i have a question about sql query. i want to duplicate a one row with same value, The number of lines must be same with the value of quantity

示例我有1条这样的数据

example i have 1 data like this

Item  ItemName   Quantity
B100  Mouse      10

但我想成为这样

Item  ItemName   Quantity
B100  Mouse      10
B100  Mouse      10
B100  Mouse      10
B100  Mouse      10
B100  Mouse      10
B100  Mouse      10
B100  Mouse      10
B100  Mouse      10
B100  Mouse      10
B100  Mouse      10

你能帮我吗

感谢之前

推荐答案

创建一个numbers表并对其执行一个CROSS JOIN

Create a numbers table and just do a CROSS JOIN with it

select Item , ItemName ,  Quantity
from yourtable A
cross join (select num from numbers) b
where a.Quantity <= b.num

要在Mysql中生成序号，请检查以下答案

To generate sequential numbers in Mysql check the below answers

• 在MySQL中生成整数序列
• 在MySQL中生成一系列数字

• generate an integer sequence in MySQL
• Generating a range of numbers in MySQL

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