使用IF/CASE语句在MYSQL中查找字符串中是否存在子字符串

Question

I have a column which has a list of products in each row. eg:

• bat,ball,gloves
• bat,gloves
• shoes,gloves

I want to make a new column for each of the product, which will have a value of 1 or 0 depending on if that product exists in that row.

I'm using the following code right now:

select
*,
CASE WHEN product_name LIKE '%bat%' THEN 1 else 0 END AS bat,
CASE WHEN product_name LIKE '%gloves%' THEN 1 else 0 END AS gloves
from products

It does not work. Kindly help

Answer 1

You can use handy MysQL function find_in_set() to check if a value belongs to a comma-separated list:

select
    p.*,
    find_in_set('bat', product_name) > 0 bat
    find_in_set('gloves', product_name) > 0 gloves
from products p

If the value is found in the CSV list, find_in_set() returns a number between 1 and N that represents its position; else it returns 0 (or null if the searched CSV list is null ). So basically, to check if a value belong to the CSV list, you just need to check if the value returned by find_in_set() is strictly above 0 .