SQL Code Smells

Question

Could you please list some of the bad practices in SQL, that novice people do?

I have found the use of "WHILE loop" in scenarios which could be resolved using set operations.

Another example is inserting data only if it does not exist. This can be achieved using LEFT OUTER JOIN. Some people go for "IF"

Any other thoughts?

Edit: What I am looking for is specific scenarios (as mentioned in the question) that could be achieved using SQL without using procedural constructs

Thanks

Lijo

Answer 1

Here are some I have seen:

• Using cursors instead of equivalent (and faster) set operations (joins etc).
• Dynamic SQL for everything.
• Code that is open to SQL Injection attacks.
• Full outer joins even when they are not needed.
• Huge stored procedures (hundreds/thousands of lines).
• No comments.