Config SQL*Plus to return nothing but data

Question

I need to write a simple shell function that returns a single field from an Oracle DB. Think of it as for example SELECT 'ABC' FROM dual; and ABC is what I am after.

Here is my function:

function getSomeOraVal
{
sqlplus $USER/$PASSWD@$ORADB<<!!

SET sqlprompt '' 
SET sqlnumber off 

SET verify off
SET pages 0
SET echo off
SET head on
SET feedback off
SET feed off
SET serveroutput on
SET escape '\'

VARIABLE  v_someVal VARCHAR2(30);

BEGIN
SELECT 'ABC' INTO v_someVal FROM dual;
END;
/

SELECT :v_someVal FROM dual;

!!
}

However, I want to pipe the sqlplus output (data only -> 'ABC') into a shell variable, which the function then returns and can be called from other shell scripts. Unfortunately, sqlplus returns a whole lot of garbage, such as "Welcome to Oracle" on top and "Disconnected..." in the bottom.

How can I extract just the data from a SQL result set, or in this case a single value and pass it into a UNIX variable for further manipulation within the shell?

Thanks

Answer 1

There are a few different approaches in this askTom thread on returning values from SQL*Plus to a shell script.

One common approach is to select a constant token in addition to the value that you want to return (in Tom's example, that is the string "KEEP") and then use sed (or your favorite command-line parser) to extract the data you're actually interested in

#!/bin/ksh

x=`sqlplus / <<endl | grep KEEP | sed 's/KEEP//;s/[   ]//g'
select 'KEEP' , max(sal) from emp;
exit
endl`

echo the answer is $x

Other approaches, such as approaches that allow you to read multiple lines of output are also discussed in that thread.

If you don't want the header to be printed, you should be specifying

set head off

in your SQL*Plus script-- I'm not sure why you're explicitly setting the header on in the script if you don't want the header... Do you want to keep some part of the header?

Answer 2

Based on Justin's answer (which is great), when you only need to select one number (or token), I consider this a little shorter, yet more readable version:

x=`sqlplus -S / <<< "select 'KEEP' , max(sal) from emp;" | awk '/KEEP/{print $2}'`