问题
I am using MySQL and MySQL Workbench 5.2 CE. When I try to concatenate 2 columns, last_name and first_name, it doesn\'t work :
select first_name + last_name as \"Name\" from test.student
回答1:
MySQL is different from most DBMSs use of + or || for concatenation. It uses the CONCAT function:
SELECT CONCAT(first_name, " ", last_name) AS Name FROM test.student
As @eggyal pointed out in comments, you can enable string concatenation with the || operator in MySQL by setting the PIPES_AS_CONCAT SQL mode.
回答2:
Try:
select concat(first_name,last_name) as "Name" from test.student
or, better:
select concat(first_name," ",last_name) as "Name" from test.student
回答3:
Use concat() function instead of + like this:
select concat(firstname, lastname) as "Name" from test.student
回答4:
That's not the way to concat in MYSQL. Use the CONCAT function Have a look here: http://dev.mysql.com/doc/refman/4.1/en/string-functions.html#function_concat
来源：https://stackoverflow.com/questions/5975958/string-concatenation-in-mysql