SQL is a standard language for storing, manipulating and retrieving data in databases.

definition  - SELECT  *  |{[DISTINCT] column|expression [alias],...} FROM table;
  • SELECT identifies the columns to be displayed
  • FROM identifies the table containing those columns

1. Selecting All Columns


code --> select * from po_lines_all ;


2. Selecting Specific Columns


Code --> SELECT PO_LINE_ID,ITEM_DESCRIPTION FROM po_lines_all;



3.Using Column Aliases

Code --> SELECT PO_LINE_ID ACCOUNT_ID ,ITEM_DESCRIPTION Description FROM po_lines_all;



4.Concatenation Operator

Code --> SELECT PO_LINE_ID || ITEM_DESCRIPTION  FROM po_lines_all;

5.Using Arithmetic Operators



6.Operator Precedence

7.Duplicate Rows


8.Displaying Table Structure