How to update data whose field value is null in mysql

Update the null field value to 'none'

The first thought is:

Update 'client' set 'Company' = 'none' WHERE 'Company' = NULL

Result error

The correct method IS to use the is null condition.

Update 'client' set 'Company' = 'none' WHERE 'Company' IS NULL

Example

Mysql> desc 'table'
+ ------- +
| Column |
+ ------- +
| NULL |
+ ------- +

For column field + 10

Mysql> update 'table' set 'column '+ 10
+ ------- +
| Column |
+ ------- +
| NULL |
+ ------- +
0 rows are affected. (The query takes 0.0002 seconds)

Returns NULL.

Mysql> update 'table' set IFNULL ('column ', 0) + 10
+ ------- +
| Column |
+ ------- +
| 10 |
+ ------- +
1 line is affected. (The query takes 0.0002 seconds)