Is it possible to use sql%rowcount for SELECT? - oracle

Question

The code below may return more than one row. Will sql%rowcount return the number of rows fetched?
select * from emp where empname = 'Justin' and dept='IT'
if sql%rowcount>0
...
This is my sample proc; am I using sql%rowcount in correct way?
CREATE PROCEDURE Procn(in_Hid IN VARCHAR2,outInststatus OUT VARCHAR2,outSockid IN NUMBER,outport OUT VARCHAR2,outIP OUT VARCHAR2,outretvalue OUT NUMBER)
AS
BEGIN
select INST_STATUS into outInststatus from TINST_child where INST_ID = in_Hid and INST_STATUS = 'Y';
if outInststatus = 'Y' then
select PORT_NUMBER,STATIC_IP into outport,outIP from TINST where INST_ID = in_Hid and IP_PORT_STATUS = 'Y';
if sql%rowcount >= 1 then
select SOCK_ID into outSockid from TINST where PORT_NUMBER = outport AND STATIC_IP = outIP;
outretvalue := 0;
else
outretvalue := -12;
end if;
EXCEPTION
WHEN NO_DATA_FOUND THEN
outretvalue := -13;
end if;
END;

Answer 1

Yes, you can use SQL%ROWCOUNT. It's valid in PL/SQL.
However, in PL/SQL the result of your query needs to go somewhere e.g. into a PL/SQL table. PL/SQL will never send the result to the output (terminal, window etc.). So SELECT * FROM won't work.
Your code could look like this:
DECLARE
TYPE emp_t ...;
emp_tab emp_t;
BEGIN
SELECT *
BULK COLLECT INTO emp_tab
FROM emp
WHERE empname = 'Justin' AND dept='IT';
IF sql%rowcount > 0 THEN
.. do something ...
END IF;
END;
/
Update:
The updated questions suggests that you're looking for something else.
Option 1: Use exceptions
If there are 0 rows or more than 1 row, these cases are handled separately (as errors):
BEGIN
select PORT_NUMBER,STATIC_IP into outport, outIP
from TINST
where INST_ID = in_Hid AND IP_PORT_STATUS = 'Y';
EXCEPTION
WHEN NO_DATA_FOUND THEN
outretvalue := -12;
RETURN;
WHEN TOO_MANY_ROWS THEN
outretvalue := -13;
RETURN;
END;
Option 2: Use aggregations
Using aggregations, the query will always return exactly one row. If now source row matched the WHERE clause, then both result values will be NULL. If there WHERE clause matched more than one row, the maximum will be taken.
Note that this query might return a port number and an IP address that originally were not on the same row.
select MAX(PORT_NUMBER), MAX(STATIC_IP) into outport, outIP
from TINST
where INST_ID = in_Hid AND IP_PORT_STATUS = 'Y';
IF outport IS NULL OR outIP IS NULL THEN
outretvalue := -12;
RETURN;
END IF;
Option 3: Use ROWNUM
This query returns at most one row. If no row matched the WHERE clause, an exception is thrown and needs to be handled:
BEGIN
select PORT_NUMBER, STATIC_IP into outport, outIP
from TINST
where INST_ID = in_Hid AND IP_PORT_STATUS = 'Y'
AND ROWNUM = 1;
EXCEPTION
WHEN NO_DATA_FOUND THEN
outretvalue := -12;
RETURN;
END;

Answer 2

Based on your comment
If 2nd 'select' query returns more than one row i want to take the first one and process with it
... this ought to work, but perhaps not quite as you expect, as you haven't defined what the 'first one' means.
CREATE PROCEDURE Procn(in_Hid IN VARCHAR2, outInststatus OUT VARCHAR2,
outSockid IN NUMBER, outport OUT VARCHAR2, outIP OUT VARCHAR2,
outretvalue OUT NUMBER)
AS
BEGIN
select INST_STATUS into outInststatus
from TINST_child
where INST_ID = in_Hid and INST_STATUS = 'Y';
-- no need to check if outInstatus is Y, that's all it can be here
-- restricting with `rownum` means you'll get at most one row, so you will
-- not get too_many_rows. But it will be an arbitrary row - you have no
-- criteria to determine which of the multiple rows you want. And you can
-- still get no_data_found which will go to the same exception and set -12
select PORT_NUMBER, STATIC_IP into outport, outIP
from TINST
where INST_ID = in_Hid and IP_PORT_STATUS = 'Y'
and rownum < 2;
-- no need to check sql%rowcount; it can only be 1 here
-- not clear if this can return multiple rows too, and what should happen
-- if it can; could use rownum restriction but with the same caveats
select SOCK_ID into outSockid
from TINST
where PORT_NUMBER = outport AND STATIC_IP = outIP;
outretvalue := 0;
EXCEPTION
WHEN NO_DATA_FOUND THEN
outretvalue := -12;
END;
The exception handler applies to the whole block. If any of the select statements find no rows, the no_data_found exception will be handled by that block and will set outretvalue to -12.
If you want a different outretvalue for each select then you can wrap them in sub-blocks, each with their own exception handling section:
CREATE PROCEDURE Procn(in_Hid IN VARCHAR2, outInststatus OUT VARCHAR2,
outSockid IN NUMBER, outport OUT VARCHAR2, outIP OUT VARCHAR2,
outretvalue OUT NUMBER)
AS
BEGIN
BEGIN
select INST_STATUS into outInststatus
from TINST_child
where INST_ID = in_Hid and INST_STATUS = 'Y';
EXCEPTION
WHEN NO_DATA_FOUND THEN
outretvalue := -12;
END;
BEGIN
select PORT_NUMBER, STATIC_IP into outport, outIP
from TINST
where INST_ID = in_Hid and IP_PORT_STATUS = 'Y'
and rownum < 2;
EXCEPTION
WHEN NO_DATA_FOUND THEN
outretvalue := -13;
END;
BEGIN
select SOCK_ID into outSockid
from TINST
where PORT_NUMBER = outport AND STATIC_IP = outIP;
EXCEPTION
WHEN NO_DATA_FOUND THEN
outretvalue := -14;
END;
outretvalue := 0;
END;
You only need to do that if the caller needs to know which select failed, and if you never really expect any of them to fail then it's probably more common not to catch the exception at all and let the caller see the raw no_data_found and decide what to do. Depends what the exception condition means to you and your application though.