Question

I have 2 tables:

pages table contains field id

pages2categories table contains fields page and category

I want to select records from the pages table

where (there is a record in the pages2categories table 
WHERE pages2categories::page = pages::id AND pages2categories:: category = 'X') 
AND (there is also a record in the pages2categories table WHERE pages2categories::page = pages::id AND pages2categories:: category = 'Y') 
AND (there is also a record in the pages2categories table WHERE pages2categories::page = pages::id AND pages2categories:: category = 'Z')

In other words, returning a record from the pages table only if all three matching records exist in the pages2categories table.

EXAMPLE:

pages::id

1

2

3

pages2categories::page, pages2categories::category

1, x

1, y

2, x

2, y

2, z

3, x

Result should return just record 2 from the pages table.

I hope this is clear. Thanks!

Answer 1

You can also use this:

SELECT * FROM TABLE1 A
WHERE EXISTS (SELECT * FROm TABLE2 B WHERE A.ID = B.ID AND B.category = 'X') 
AND EXISTS (SELECT * FROm TABLE2 B WHERE A.ID = B.ID AND B.category = 'Y')
AND EXISTS (SELECT * FROm TABLE2 B WHERE A.ID = B.ID AND B.category = 'Z')