Will return 0 or false:
```SQL
SELECT "5,18,5,7,9,2" REGEXP "[[:<:]](8)[[:>:]]"
```

Will return 1 or true:
```SQL
SELECT "5,18,5,7,9,2" REGEXP "[[:<:]](5)[[:>:]]"
```
**For Redshift you must use `~` instead REGEXP on above statements:**
```SQL
SELECT "5,18,5,7,9,2" ~ "[[:<:]](5)[[:>:]]"
```

MySQL have a a function called find_in_set():
```SQL
SELECT FIND_IN_SET("c", "a,b,c,d,e");
```