You can search a comma-delimited list in SQL by using FIND_IN_SET. Although its considered poor design, it is possible to nest values in a field as a comma delimited list:
fruit_table
| fruit | tags |
|---|---|
| apple | red,delicious |
| banana | yellow |
You can query tags using FIND_IN_SET:
SELECT * FROM fruit_table WHERE FIND_IN_SET('delicious', tags)The above query will return
| fruit | tags |
|---|---|
| apple | red,delicious |
Normally you would want to normalize this kind of data, but it may be convenient in some instances.