sql - select query on two tables with no unique keys -

i have 2 tables.

table1

 col1   col2  col3
 100        1000  100        1000 100        1002 100    b     1003 100    c     1004 

table2

 col1   col2  colc
 100        1x  100        2x   100        3x 100    b     4x 100    c     5x 

in above table colc value unique.

i want ouptput this, colc values unique here also.

 col1   col2  col3  colc
 100        1000  1x  100        1000  2x   100        1002  3x 100    b     1003  4x 100    c     1004  5x 

i have use col1 , col2 key join.

is possible that. got duplicates comming in first 2 records, when tried inner , left outer joins. tia

something this?

select   a.col1,   a.col2,   a.col3,   b.colc  (   select     row_number() on (partition col1, col2 order 1) r,     col1,     col2       table1   ) a,  (   select     row_number() on (partition col1, col2 order 1) r,     col1,     col2       table2   ) b   a.r = b.r ,         a.col1 = b.col1 ,         a.col2 = b.col2;