Mysql null safe comparison

The way I prefer to do it is by coalescing to otherwise impossible value. For example, this. The workaround is to use e. Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams?

Collectives on Stack Overflow. Learn more. Asked 9 years, 10 months ago. Active 1 year, 6 months ago. Viewed 70k times. Improve this question. Add a comment. Active Oldest Votes. Any arithmetic comparison with 'NULL' will return false. NULL-safe equal and not equal operators in mysql. Null safe equals operator.

Null safe not equals operator [NOT ]. If normal! Next Topics. Uppercase first letter ucfirst in mysql with example. How to manage users in Mysql? How to drop all constraints in Mysql? How to ignore constraints while insert,update or delete records in Mysql? Previous Topics. Automatic insert and update timestamp on Mysql table's.

How to Create dynamic pivot query in mysql with Example. Remove decimal places without rounding in mysql using truncate with Example. This is what confuses programmers who are experienced in other languages. So as our query is evaluated, it is going to look like this:. This comparison is also going to return unknown.

We can see from the truth table earlier that NOT unknown is going to return unknown. So now our query has become:. The result not being false is not enough.

The value of any NULL is unknown. Again it is the unknown value of NULL. Just as it is unknown if NULL 3. Alice is excluded from the results. But it is less than or equal to 5, so he is now included in the query result. Once again, Alice is excluded from the results.

You should now be clear that this can only result in a value of unknown. We've written specific tutorials to discuss each of the more advanced comparison operators.

These topics will be covered later, or you can jump to one of these tutorials now. While using this site, you agree to have read and accepted our Terms of Service and Privacy Policy.