There are many ways you can modify a SQL query.
Here I am going to cover two types.
- Take out your production query into test region, and execute and capture results
- Test your modified query also in test region .
- Compare your results, then modify your query in production box
Online SQL is another option. Where you no need to install any SQL development Software. Then you need to create simple tables and then write your SQL and test it. This way testing is highly useful and you can tweak SQL easily.