How to combine multiple columns as one and format with custom strings?

SELECT 

CONCAT('https://example.com/estimation/create?pId=',task_p_id,'&estId=',task_est_id) as live_url,

CONCAT('http://stage.example.com/estimation/create?pId=',task_p_id,'&estId=',task_est_id) as stage_url 

FROM `ls_task` LEFT JOIN `ls_estimation` ON est_id=task_est_id LEFT JOIN `ls_project` ON p_id=task_p_id limit 10

What about the CONCAT() function?

SELECT id, CONCAT(lastname, ', ', firstname) AS name FROM `table`;

If you are going to concatenate many fields, you could also consider the CONCAT_WS() function, where the first argument is the separator for the rest of the arguments, which is added between the strings to be concatenated:

SELECT id, 
       CONCAT_WS(',', field_1, field_2, field_3, field_4) list
FROM   `table`;

use concat like :

SELECT id, CONCAT(lastname, ' , ', firstname) AS name FROM `table`;