I have the following:
CREATE Table apellidos_completo (Completo varchar (255))
INSERT INTO apellidos_completo (Completo )values ('alvarez')
UPDATE apellidos_completo set Completo = 'Rodriguez' + Completo
I do SELECT
SELECT *
FROM apellidos_completo
the result should be
'Rodriguez Alvarez'
However, the result obtained is:
(0) osea CERO
NOTE: if I do it in SQL server if it works, fine, but in MySQL it does not work out.
The union, not the sum; is done by means of the function CONCAT() , which helps me concatenate or join several values, guide yourself by this example
SET @varUno = 'Pack';
SET @varDos = ' nombre';
MariaDB [(none)]> SELECT CONCAT(@varUno, @varDos) AS Mensaje;
+-------------+
| Mensaje |
+-------------+
| Pack nombre |
+-------------+
This function, need inside and separated by commas the values that you want to join, finally with an alias we give a temporary name to the table that has to show me the results
Within your code you return 0 because you are taking or trying to take the values as those that you can add by using the + sign, since it is not of a numeric type it returns 0
In any case, what you are looking for is not the sum of the text strings, but the concatenation of them that is very different