need help implementing IF..ELSE

aurel1412 · #1 (**permalink**) 12-13-03, 01:15

Hi,

im really now with sql so can anyone give an example on this problem?
i dont know how to implement this kind of logic in sql:

if (ID != null)
print name
else print "not available"

i was thinking about using case, but i'm not sure how to implement printing a string in a case statement using sql
sorry for the language term...i'm really used to java, so i always think in java term when im doing programming

thanks

aus · #2 (**permalink**) 12-13-03, 02:19

In MySQL, you want to use a statement like:

SELECT IF(ISNULL(ID), 'Not Available', Name), ...

aurel1412 · #3 (**permalink**) 12-16-03, 06:37

this is how i do it....

SELECT IF(ISNULL("Student"."ID"),
'Not Available',
"Student"."LastName"),
COMPUTER.SerialNumber "Serial Number"
FROM COMPUTER left join Student
ON "Student"."ID" = COMPUTER.ID
ORDER BY COMPUTER.SerialNumber
;

but it gives me this error:

SELECT IF(ISNULL("PERSON"."PersonID"), 'Not Available', "PERSON"."LastName"),
*
ERROR at line 1:
ORA-00904: "IF": invalid identifier

What's wrong??????
someone PLSSSS HELP

r937 · #4 (**permalink**) 12-16-03, 06:51

why are you getting an oracle error message from mysql?

this is the mysql forum

try this, it is standard sql and works in all databases that support standard sql --

Code:

select case when  is null
            then 'not available'
            else student.lastname
         end
     , computer.serialnumber as "serial number"
  from computer 
left outer
  join student
    on computer.id = student.id
order 
    by computer.serialnumber

rudy
http://r937.com/

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