INSERT

The INSERT ... VALUES and INSERT ... SET forms of the statements are used to insert rows which have values that are explicitly specified.

INSERT [IGNORE]

       [INTO] tbl_name [(col_name,...)]

       {VALUES | VALUE} ({expr | DEFAULT},...),(...),...

       [ ON DUPLICATE KEY UPDATE col_name=expr

       [, col_name=expr] ... ]

OR

INSERT [IGNORE]
       [INTO] tbl_name
       SET col_name={expr | DEFAULT}, ...
       [ ON DUPLICATE KEY UPDATE col_name=expr
       [, col_name=expr] ... ]

The INSERT ...SELECT form inserts rows selected from another table or tables.

INSERT [IGNORE]    
       [INTO] tbl_name [(col_name,...)]
       SELECT ...
       [ ON DUPLICATE KEY UPDATE  col_name=expr
       [, col_name=expr] ... ]

You can use REPLACE instead of INSERT to overwrite old rows.

The following statement
will create a row with the fields with its default values:

INSERT INTO tbl_name () VALUES();

If you want to insert a value[dependent on the previous
column] into a  column, then you can use
expressions.

INSERT INTO tbl_name (col1,col2) VALUES(20,col1*5); 

This will create a row with a value 20 in col1 and 100 (i.e. 20*5) in col2. 

NOTE: You cannot use the columns in the expressions before they have been assigned values.

SO THE FOLLOWING STATEMENT BECOMES ILLEAGAL:

INSERT INTO tbl_name (col1,col2) VALUES(col2*5,20);