Query with multiple values in a column

Question

I have a table like:

id     name            children
1      Roberto         Michael,Dia
2      Maria           John,Alex
3      Mary            Alexandre,Dia         


        

Answer 1

That's why you'd want to have two tables here.

parents:
id  name
1   Roberto  
2   Maria
3   Mary

children:
id  parentid name
1   1        Michael
2   1        Dia
3   2        John
4   2        Alex
5   3        Alexandre
6   3        Diana

And now you can query this much more effectively with a join or an exists:

SELECT *
FROM Parents
WHERE EXISTS(
    SELECT * 
    FROM Children 
    WHERE parentid=Parents.id 
      AND Children.name='Alex'
 )