Consider a table T1 with c1,c2,c3, and c4. Suppose c4 is removed from schema definition of T1. Instead a new table T2 is defined with c1, and c4 as its coluns. Now SELECT c1,c2,c3,c4 FROM t1 fails as an embedded query, in a host language. Resolve this issue so that no chnage in the form of a software patch is required in the application software that is using the embedded query..... Then i wanna know the benefits of Outer Join. My idea of first question is that we use SELECT * instead of specifying eahc column name in the SELECT Query. and in 2nd i think it tells about the voilations of that are occured in a join, i.e. value in Table A such that nothing exists for that value on Table B.