MySQL when querying a field result is empty and assigned a value

1 Code

1.1 When the current field is empty, the result of the query returns "None" and the frequency of statistics occurs

Select Case when field is null then ' none ' else field end  as field, Count (1) as counts from table group by field;

1.2 When the current field is an empty string, the result of the query returns "None" and the frequency of statistics occurs

Select Case when field = ' Then ' none ' else field end  as field, Count (1) as counts from table group by field;

1.3 When the current field is empty, the result of the query returns "None"

The Select Case when field is null and then ' none ' else field end as  field from table;

1.4 When the current field is a null character, the query results return "None"

Select Case when field = ' Then ' none ' else field end as  field from table;

2 Summary

Only used as a record, MySQL other related commands have Isnull,ifnull and nullif.

Ifnull, Nullif and isnull usages in the Link:mysql

MySQL when querying a field result is empty and assigned a value