Comment by MaxBarraclough

There are unit-testing frameworks for the purpose. For SQL Server there are several, [0] I've worked briefly with one called tSQLt [1] and was quite impressed. Frameworks also exist for other RDBMSs. [0]

[0] https://en.wikipedia.org/wiki/List_of_unit_testing_framework...

[1] https://tsqlt.org/user-guide/quick-start/