SQL NULL’s special, and you have to do WHERE field IS NULL
, as NULL cannot be equal to anything,
including itself (ie: NULL = NULL is always false).
More Related Contents:
- MySQL comparison with null value
- When to use NULL in MySQL tables
- How do I get SUM function in MySQL to return ‘0’ if no values are found?
- MySQL foreign key to allow NULL?
- MySQL CONCAT returns NULL if any field contain NULL
- Replace null with 0 in MySQL
- MySql Query Replace NULL with Empty String in Select
- Why in SQL NULL can’t match with NULL?
- How to do unique constraint works with NULL value in MySQL
- left join query keep a column empty
- what will be the sql query code of this “Healthcare” database?
- Rank function in MySQL
- MySQL 8.0 – Client does not support authentication protocol requested by server; consider upgrading MySQL client
- Can’t connect to MySQL server error 111 [closed]
- Find nearest latitude/longitude with an SQL query
- MySQL query String contains
- Mysql localhost != 127.0.0.1?
- How do I decide when to use right joins/left joins or inner joins Or how to determine which table is on which side?
- Capitalize first letter. MySQL
- #1055 – Expression of SELECT list is not in GROUP BY clause and contains nonaggregated column this is incompatible with sql_mode=only_full_group_by
- MySQL remote connection fails with “unknown authentication method”
- Import MySQL database into a SQL Server
- How does MySQL’s ORDER BY RAND() work?
- How create json format with group-concat mysql?
- DETERMINISTIC, NO SQL, or READS SQL DATA in its declaration and binary logging is enabled
- Correct way to keep pooled connections alive (or time them out and get fresh ones) during longer inactivity for MySQL, Grails 2 app
- MySQL: Setting sql_mode permanently
- MySQL: how to index an “OR” clause
- Is it possible to count two columns in the same query
- mySQL regex in the where clause