Difference between [table1.column1=table2.column1] and [table1.column1=1 AND table2.column1=1]

Question

I don't know if there are any terms for these statements: I have table1 and table2

table1

id link_id
1     1
1     2
1     3

table2

id link_url
1     www.a
2     www.b
3     www.c

And two different MYSQL Statements:

SELECT table1.id as id, table2.link_url as link_url FROM table1, table2  WHERE table1.link_id =1 and table2.id=1

SELECT table1.id as id, table2.link_url as link_url FROM table1, table2  WHERE table1.link_id=table2.id

I understand that they both return the same results.

Is there any difference in using either of them or doesn't it matter at all?

Answer 1

Yes there is Difference. First Statement Returns only one row as you have set table1.link_id=1 and table2.id=1

Second Statement will Return every row which have link_id value in table1 similar to id value table2

Answer 2

link_id=table2.id select all data of your table where both coloumn are same .But WHERE table1.link_id =1 and table2.id=1 select data where link_id is 1 and id is 1.... both are diffrent

But USE JOIN is good option :-

SELECT table1.id as id, table2.link_url as link_url 
FROM table1 join  table2  
on table1.link_id=table2.id
WHERE table1.link_id =1