Function with select if statement query

Question

Hi,
I want to use if condition in select statement in function.
But i implemented in case too ,its taking more time to return the value while using case statement.
My function is like this
create or replace FUNCTION GET_CODE
(pv_type IN table1.type%TYPE,
pv_desc1 IN table2.type%TYPE,
pv_desc2 IN table3.type%TYPE)
RETURN varchar2(35 byte)
IS
V_ret_string varchar2(35 byte);
BEGIN
SELECT case when(table2.xxx like 'fff%') then 1
when (table3.yyy like 'fff%') then 2
when (table4.zzz like 'fff%') then 3
else table1.aaa
INTO V_ret_string
FROM
table1 a,table2 b,table3 c table4 d
WHERE
table1.column1=table2.column1
and (table1.column2=table3.column1 or table1.column2=table4.column1) and
UPPER(b.type) = UPPER(pv_type) and
(UPPER(c.desc) = UPPER(pv_desc1) or UPPER(d.desc1) = UPPER(pv_desc2)) ;
RETURN V_ret_string;
END GET_TRANSACTION_CODE;
Pls help me how to use if condition.
Regards,
Punitha

Answer 1

936698 wrote:
Hi,
I want to use if condition in select statement in function.Oracle SQL SELECT statement does not support IF condition syntax. But what it does is CASE and DECODE. And CASE statement is sufficient to achieve what ever you want to do with IF condition.
But i implemented in case too ,its taking more time to return the value while using case statement.So the issue is not with CASE its with the SELECT Statement. What you have to do is Isolate your SELECT statement and try to tune it for performance.
To do that i would suggest you to read the folloing threads which could be of good use.
{thread:id=501834} and {thread:id=863295}.
>
>
My function is like this
create or replace FUNCTION GET_CODE
(pv_type IN table1.type%TYPE,
pv_desc1 IN table2.type%TYPE,
pv_desc2 IN table3.type%TYPE)
RETURN varchar2(35 byte)
IS
V_ret_string varchar2(35 byte);
BEGIN
SELECT case when(table2.xxx like 'fff%') then 1
when (table3.yyy like 'fff%') then 2
when (table4.zzz like 'fff%') then 3
else table1.aaa
INTO V_ret_string
FROM
table1 a,table2 b,table3 c table4 d
WHERE
table1.column1=table2.column1
and (table1.column2=table3.column1 or table1.column2=table4.column1) and
UPPER(b.type) = UPPER(pv_type) and
(UPPER(c.desc) = UPPER(pv_desc1) or UPPER(d.desc1) = UPPER(pv_desc2)) ;
RETURN V_ret_string;
END GET_TRANSACTION_CODE;When ever posting code please make sure the code is well formatted and you use the {noformat}{noformat} tag to preserve the format. An unformatted code is very hard to read.
The usage of the tag is like this.
<place your code here>\