how to write a if condition within a select statement?

I have a column which needs to be populated with ture/false/(N/A) data. This column is part of a select statement So, How can i achieve this?

SELECT distinct 
program_id, 
prog_name,
Eitc_Active_Switch as Prog_Status,
progmap.client_id,
progmap.ORG_ID,
sec.calwinexists_ind as interface,
sec.Client_name
FROM ref_programs prog (nolock)
LEFT OUTER JOIN ref_county_program_map progmap (nolock)         
ON progmap.program_id=prog.prog_id AND progmap.CLIENT_ID=prog.CLIENT_ID 
INNER jo开发者_开发问答in sec_clients sec (nolock)
on sec.client_id=progmap.Client_id

'sec.calwinexists_ind as interface' is the column. the true/false should be displayed for only three records (AMC, AMBD, ACMNI) and 'N/A' for the rest of the records

Can anyone help me?

You should use CASE expression.

Example:

SELECT name,salary,
CASE    
WHEN  salary <= 2000 THEN 'low'
WHEN  salary > 2000 AND salary <= 3000 THEN 'average'
WHEN  salary > 3000 THEN 'high'
END AS salary_level
FROM employees
ORDER BY salary ASC

And in this way you should adapt your query to match your needs.

Could you use a CASE WHEN control. Take a look at: http://dev.mysql.com/doc/refman/4.1/pt/control-flow-functions.html