In a MySQL query I am doing a GROUP BY with a text field. Due to the nature of the original data, some rows are contain empty strings for this field, and others are true null.
When grouping, how can I group empty string and null together, treating both as null?
This can be accomplished by SELECT CASE. There may be a simpler way I do not know of.
The format of SELECT CASE is
SELECT
CASE
WHEN table_name.text_field IS NULL OR table_name.text_field = ''
THEN null
ELSE table.text_field
END as new_field_name,
other_field, another_field, ...rest of query...
So you see, you can CASE together values with WHEN/THEN and default to the real value by ELSE.
