Is it possible to conditionally select columns in MySQL?

MySQL as count group by?

• select count(1), domain_id as "row_count", "domain_id" from rtr_traffic_mo group by domain_id; I gave the above query in mysql but instead of two columns its showing 3 columns. I basically want count(1) to be represented as row_count and domain_id as domain_id. It would be of great help if you could tell me what 1 is for in count(1) and what is the significance of 'group by' here. What if I dont give that.

• Answer:

  By using 'group by domain_id;' you are instructing to show each domain_id only once in the result set. and in the 'select' clause you may perform certain functions on the data in different fields of the records having same domain_id. If you want to get the number of occurrences of each domain_id. you may use following query. select count(domain_id) as row_count, domain_id from rtr_traffic_mo group by domain_id;