Repeat a result row multiple times by value in row

问题

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

example i have 1 data like this

Item  ItemName   Quantity
B100  Mouse      10

but i want to be like this

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

can you help me

Thanks Before

回答1:

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

To generate sequential numbers in Mysql check the below answers

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

来源：https://stackoverflow.com/questions/34253461/repeat-a-result-row-multiple-times-by-value-in-row