International SQL-Ledger Network Association

First check the AR amount without payment:

 
 SELECT SUM(amount) FROM acc_trans WHERE trans_id = ID and chart_id in (select id from chart where link not like '%_paid%');

Then check payment amount:

  SELECT SUM(amount) FROM acc_trans WHERE trans_id = ID and chart_id in (select id from chart where link like '%_paid%');
  

Or run a query to compare all values from the two tables:

   SELECT ar.id, invnumber, ar.amount, (SELECT SUM(amount) FROM acc_trans ac WHERE ac.trans_id = ar.id AND ac.chart_id IN (SELECT id FROM chart WHERE link NOT LIKE '%_paid%')) amount2 FROM ar WHERE paid <> 0 AND id IN (SELECT trans_id FROM acc_trans GROUP BY trans_id HAVING SUM(amount) = 0) GROUP BY 1,2,3;
   

Another query to check if transaction is completely balanced:

  SELECT SUM(amount) FROM acc_trans WHERE trans_id = ID