Q:

how to select * from tableA where columnA values don't start with letter 'F'

Can I have a SQL query to get the data from columna in tableA whose values don't start with 'f' ?
For example:  
select * from  tableA where columnA

where values don't start with letter 'F'.

A:

For a MSSQL Scenario, you should be able to use the "NOT" operator in conjunction with the LIKE operator.  So your SQL would look roughly like
select * from tableA where columnA NOT LIKE  'F%'

A:

@Evan: the statement about SQL Server being case insensitive is actually not entirely true.  Case sensitivity depends on collation.  The server has a collation (chosen on install), a database has a collation (chosen on DB creation) and text columns have a collation (chosen when creating the column).  When no collation is specified on DB creation, the server collation will be the default.  When no collation specified on column creation it gets the same collation as the DB.
But in most cases, people (luckily) install their server using a case insensitive collation, such as Latin1_General_CI_AS.  CI = case insensitive, AS = accent sensitive.
On SQL Server, if I needed to get both the small f and capital F, I would go for:
where columnA NOT LIKE 'F%' and columnA NOT LIKE 'f%'

PS: I'm adding this as "answer" because I don't see any option to comment on an existing answer - I'm still new here... If anyone has an explanation why I don't get this option, don't hesitate to contact me.
Regards, Valentino.

A:

SELECT columnA
  FROM tableA
 WHERE SUBSTR(columnA,1,1) <> 'f'

If you need both 'f' and 'F':
SELECT columnA
  FROM tableA
 WHERE SUBSTR(columnA,1,1) NOT IN ('f','F')

Going off of Lerxst's example, some DBMSs will also let you do fun stuff like this:
SELECT columnA
  FROM tableA
 WHERE columnA NOT LIKE ALL ('f%','F%')

