Question

I have a database with two main tables notes and labels. They have a many-to-many relationship (similar to how stackoverflow.com has questions with labels). What I am wondering is how can I search for a note using multiple labels using SQL?

For example if I have a note ‘test’ with three labels ‘one’, ‘two’, and ‘three’ and I have a second note ‘test2’ with labels ‘one’ and ‘two’ what is the SQL query that will find all the notes that are associated with labels ‘one’ and ‘two’?

Answer 1

To obtain the details of notes that have both labels ‘One’ and ‘Two’:

select * from notes where note_id in ( select note_id from labels where label = 'One'   intersect   select note_id from labels where label = 'Two' )