What common mistake do developers make with Where clauses, why does the mistake cause problems, and what is the safer approach?

What common mistake do developers make with Where clauses, why does the mistake cause problems, and what is the safer approach? One recurring problem with where clauses is applying it without understanding the boundary it protects. Concatenating request parameters into raw SQL expressions instead of passing values through the query builder bindings. In addition, Where conditions restrict rows according to values, ranges and other query predicates. Safer engineering approach: keep the responsibility in the correct layer, use the framework's supported API, validate and authorize inputs, avoid hidden side effects, and verify the behavior with tests.