Help on a simple SQLstatement

Question

If I had to use a select statement in order to do something that would normally involve an "If..Then" , what would this select statement look like?
I'm trying to do the following:
If A = "value1" then B = "value 2"
and
If A IN ("value3", "value4", ...) then B /= "value2"
Sorry for something that I'm sure is a simple answer. Thanks in advance.

Answer 1

here is simple example
SQL> select empno,ename, (CASE when deptno=10 then
2 'TEN'
3 END) deptno
  4  from emp where deptno=10  ;
     EMPNO ENAME                                              DEPTNO
      7782 CLARK                                              TEN
      7839 KING                                               TEN
      7934 MI_LL_ER                                           TEN
      7501 T*_1NU                                             TEN