MySQL IFNULL() function usage in SELECT queries
We all know as SQL professionals that the NULL marker is a special case. Oftentimes, you have NULL‘s stored in your tables, and that’s fine. Suppose you want to present an alternative value in query results where some of the columns have NULL? This is a perfect opportunity (but not the only) to use the IFNULL() function. I find IFNULL() quite useful when exporting query results to a CSV file or other type of flat file, providing something more meaningful than the NULL word itself. However, you only have one substitute for the NULL value when using IFNULL(), so keep that in mind. Continue reading and see examples using IFNULL() in SELECT queries…
OS, Software, and DB used:
- OpenSuse Leap 15.1
- MySQL 8.0.20
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There are a couple of NULL‘s in table ‘ages_1’:
MySQL localhost:33060+ ssl practice SQL > SELECT * FROM ages_1;
+ — — — — +
| an_age |
+ — — — — +
| 12 |
| 44 |
| NULL |
| NULL |
| 22 |
| 17 |
+ — — — — +
6 rows in set (0.0010 sec)
