SELECT column1, column2, columnN
FROM table_name
WHERE [CONDITION | EXPRESSION];

SELECT column1, column2, columnN
FROM table_name
WHERE SINGLE VALUE MATCHTING EXPRESSION;

testdb# select * from COMPANY;
 id | name  | age | address   | salary
----+-------+-----+-----------+--------
  1 | Paul  |  32 | California|  20000
  2 | Allen |  25 | Texas     |  15000
  3 | Teddy |  23 | Norway    |  20000
  4 | Mark  |  25 | Rich-Mond |  65000
  5 | David |  27 | Texas     |  85000
  6 | Kim   |  22 | South-Hall|  45000
  7 | James |  24 | Houston   |  10000
(7 rows)

testdb=# SELECT * FROM COMPANY WHERE SALARY = 10000;

id | name  | age | address  | salary
----+-------+-----+----------+--------
  7 | James |  24 | Houston  |  10000
(1 row)

SELECT numerical_expression as  OPERATION_NAME
[FROM table_name WHERE CONDITION] ;

testdb=# SELECT (15 + 6) AS ADDITION ;

addition
----------
       21
(1 row)

testdb=# SELECT COUNT(*) AS "RECORDS" FROM COMPANY;

RECORDS
---------
       7
(1 row)

testdb=#  SELECT CURRENT_TIMESTAMP;

now
-------------------------------
 2013-05-06 14:38:28.078+05:30
(1 row)