Batch scripting Return result into a variable - windows

Question

I am creating a generic script that will parse a statement and return the result. I have done so in shell, but don't know how this can happen in batch scripting
Script 1 Main script (main.bat).
SET Myresult=CALL child.bat "Statement"
Now Myresult should store the answer whatever I want to return in this variable.
Solution 1 : SET Myresult in Child.bat and use it in main.bat but now what if the user does not know what the variable name is .
So is their a way to return a value like in java
return xyz
xyz gets captured in the call statement elsewhere.
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PART 2
Here are the details of what I am doing .
The so called child script is getSQLResult.bat
What is does is
getSQLResult.bat -q "Select a from abc"
Now this above call statement can be used by anyone any how in any batch script .
So apart from passing a variablename(return name) or writing a for loop to parse the result set is there any simple straight forward way .

Answer 1

Option 1 - Pass the variable name
main.bat
call child.bat myresult "Statement"
echo %myresult%
child.bat
set "%~1=argument was %~2"
Option 2 - Process output of child process
main.bat
for /f "delims=" %%a in ('child.bat "Statement"') do set "myresult=%%a"
echo %myresult%
child.bat
#echo off
echo Argument was %~1
or you can use temporary files, the registry, the clipboard, ... to pass the information, but in any case if you are coding a element (your child.bat) to be reused by you or another person, you are creating an interface between this element and the rest of the code, a expected set of input arguments and a way to return information. Your question
... what if the user does not know what the variable name is?
is answered by the documentation of this interface.

Answer 2

This is the way to do it in batch:
for /f "delims=" %%a in ('echo hello world') do set myresult=%%a
echo it returned: %myresult%
(echo hello world is just an example)
Note: this will return the last (or only) line only. It can be modified to process more lines, but your example implies, there is only one line of output)
EDIT If I understand your edit correct, you want to pass just a statement to an external batchfile, which does the work and gives back the result into a variable, which is defined with the call.
REM child.bat
#echo off
set var=%1
for /f "tokens=1,*" %%i in ("%*") do (
set var=%%i
set statement="%%~j"
)
for /f "delims=" %%a in ('getSQLResult.bat -q %statement%') do set "%var%=%%a"
use it with:
call child.bat result "Select a from abc"
echo %result%
of course it will still return the last (or only) line. Can be easily modified to get the first line. If the output could be more lines, I suggest using an "array" with an counter to avoid the problems, MC ND adresses in his comment to your question. Maybe returning a filename to a file with the multiline output could be another solution.