Tutorial outline:
SQL step by step (1) -------Introduction to SQL
SQL step by step (2) -------Basic knowledge of tables
SQL step by step (3) -------Data retrieval
SQL step by step (4) -------Create table
SQL step by step (5) -------Insert data into the table
SQL step by step (6) -------Delete table
SQL step by step (7) -------Update records
SQL step by step (8) -------Delete records
SQL step by step (9) -------SELECT statement
SQL step by step (10) ------Total function
SQL step by step (11) ------GROUP BY clause
SQL step by step (12) ------HAVING clause
SQL step by step (13) ------ORDER BY clause
SQL step by step (14) ------ Combining conditions and Boolean operators
SQL step by step (15) ------IN and BETWEEN conditional operators
SQL step by step (16) ------ Mathematical operators
SQL step by step (17) ------JOIN clause
SQL step by step (18) ------Index
SQL step by step (19) ------DISTINCT and exclude copying
SQL step by step (20) ------Aliases, In and subqueries
SQL step by step (21) ------More subqueries
SQL step by step (22) ------EXISTS and ALL
SQL step by step (23) ------UNION and external connections
SQL step by step (24) ------Embedded SQL
