Oracle SQL & PL/SQL

Supressing Duplicate Rows : = Sometimes, your query results contain duplicate rows. You can eliminate such rows by adding  the keyword DISTINCT immediately after the keyword SELECT. Multiple columns can be declared after the DISTINCT qualifier. The DISTINCT qualifier affects all the selected columns, and represents a DISTINCT combination of the columns. When DISTINCT is implemented upon a column which may contain NULL values, all the NULLS in the column together treated as one DISTINCT group. A select statement should have one DISTINCT keyword. Examples :=           Ø   Select DISTINCT deptno from emp;             Ø   Select DISTINCT deptno,mgr from emp;   Ø   Select DISTINCT deptno,job from emp;        HOME