How to store sql query output in variable in shell script - bash

Question

I am trying to store the value of sql query output in a variable using shell script.
size=`${PATH_TO_CLIENT}sqlplus $IMPUSER/$IMPPWD#$ENDPOINT<< EOF
select owner, sum(bytes)/1024/1024/1024 Size_GB from dba_segments where owner = 'XXXX' group by owner;
exit;
EOF`
echo "Total data is ${size}"
The output I am getting is
**Total data is**
SQL*Plus: Release 21.0.0.0.0 - Production on Fri May 14 11:06:42 2021
Version 21.1.0.0.0
Copyright (c) 1982, 2020, Oracle. All rights reserved.
Last Successful login time: Fri May 14 2021 11:01:02 -04:00
Connected to:
Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production
Version 19.8.0.0.0
SQL>
OWNER
--------------------------------------------------------------------------------
SIZE_GB
----------
XXXXXXX
12.2345
SQL> Disconnected from Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production
Version 19.8.0.0.0
Inside the variable full connection string and sql query output all are getting stored. I just want to get value like $size=12.2345 Please tell me how to get that

Answer 1

The size value might be assigned to the current variable through use of the following code block
size=$(sqlplus -S /nolog << EOF
conn $IMPUSER/$IMPPWD#$ENDPOINT
whenever sqlerror exit sql.sqlcode
SET PAGES 0
SELECT SUM(bytes)/1024/1024/1024 FROM dba_segments WHERE owner = 'XXXX';
EOF
)
echo "Total data is "$size
where
keeping owner column and group by clause are redundant as
returning only one column value for a single schema
no need to alias the calculated value as not needed for the returning result while hiding the column title through use of SET PAGES 0 command
using direct connection is not safe, but use sqlplus -S /nolog before
schema connection in order to hide the password while listed by
anbody through ps command.

Answer 2

You can use this:
size=`${PATH_TO_CLIENT}sqlplus -s $IMPUSER/$IMPPWD#$ENDPOINT <<EOF
set echo off
set feedback off
set heading off
set pages 0
select sum(bytes)/1024/1024/1024 Size_GB from dba_segments where owner = 'SYS';
exit;
EOF`
echo "Total data is ${size}"

Answer 3

If the output is consistent with newlines, you could use:
size=`${PATH_TO_CLIENT}sqlplus $IMPUSER/$IMPPWD#$ENDPOINT<< EOF | sed -n '/^\s*SIZE_GB$/{n;n;n;p}'
select owner, sum(bytes)/1024/1024/1024 Size_GB from dba_segments where owner = 'XXXX' group by owner;
exit;
EOF`
It will return the third line after line which contains 'SIZE_GB'.