Selecting specific rows based on data from other table

Question

I have the flowing tables:

See fiddle: http://sqlfiddle.com/#!2/c1c2f/1

I'm struggling to find a way to

select software.name, systems.pc(or software.pc), systems.user

only for the rows were the software.date field matches the systems.time field meaning that fields

Answer 1

You need a JOIN, like this:

SELECT software.name, software.pc, systems.pc, systems.user
FROM software
JOIN systems
ON software.date = systems.time AND software.pc = systems.pc;

Fiddle: http://sqlfiddle.com/#!2/c1c2f/34/0

Answer 2

It is better to use aliases when querying complex data with JOINs, see following:

SELECT so.name, sy.pc, sy.user FROM software so 
JOIN systems sy
WHERE so.date = sy.time AND so.pc = sy.pc;

Specially, when you have same named columns. As in your case both tables have same column (PC).