Question about joining tables

Question

What connection is valid for the next sql statement?

select * 
from table1 tbl1, table2 tbl2 
where tbl1.id = tbl2.id

Does it return a result only if both identifiers match?

+3

firsttime May 22 '11 at 7:27

2 answers

Odded · Answer 1 · 2011-05-22T07:29:45+0000

This is an inner connection.

Yes, only records with corresponding identifiers will be returned.

This is the same as:

select * 
from table1 tbl1 
 inner join table2 tbl2 
    on tbl1.id = tbl2.id

Personally, I prefer an explicit designation INNER JOIN.

jlew · Answer 2 · 2011-05-22T07:29:59+0000

Yes, this is the ANSI-89 syntax for internal joins. ANSI-92 defines the keywords [INNER, LEFT, etc.] JOIN.