CHECKING if a value exists in a table SQL

Question

I am making a bot where I need to store the commandname and commandreply in the database. I am using mySQL Workbench.

I want to check if the commandname that the user tries to make is already in the table, and if so display that. If not, then carry on (make the command).

connection.query("SELECT commandname FROM commands WHERE EXISTS (commandname = " + args[0] + ")" 

(Where args[0] is the command name). This is what I initially thought, although I don't have much experience in SQL. I'm not sure what this would display if it exists, or if it doesn't exist.

Answer 1

SELECT count(*) FROM commands WHERE commandname = ' + args[0] + '

if it returns 0 then insert else update.

A better approach would be to update first and see how many rows are updated if it's 0 then insert, in which case it will run only 1 query most of the time (assuming update is more frequent than insert).