how to concat two columns into one with the existing column name in mysql?

Question

I want to concatenate two columns in a table with a existing column name using mysql.

An example: I am having a column FIRSTNAME and LASTNAME

Answer 1

Just Remove * from your select clause, and mention all column names explicitly and omit the FIRSTNAME column. After this write CONCAT(FIRSTNAME, ',', LASTNAME) AS FIRSTNAME. The above query will give you the only one FIRSTNAME column.