You are doing a Cross join so what will happen is that you will get T1 rowcount * t2 Count

Eg if you had 2 rows in T1 and 4 in T2 you would get 8 rows returned with data something like this returned

T1 T2

1 1

1 2

1 3

1 4

2 1

2 2

2 3

2 4

To turn it into an Inner join you need to do

Select Col1, Col4

From T1,T2

Where

T1.Col1=T2.Col3

Or a Left Join then this

Select Col1, Col4

From T1,T2

Where

T1.Col1*=T2.Col3

for a right outer the clause is =*, Unfortunately I cant remember the syntax for a Full outer.

I believe this style of left/right outer join syntax (*= etc) is being depricated over the next couple of releases of SQL server, in 2008 there is a server setting to allow the syntax, im not sure about SQL 2012 though