mysql - SELECT 中的默认值

Question

我从这个学习 SQL:http://www.w3schools.com/sql/sql_select.asp

SELECT LastName,FirstName FROM Persons

这给我看:

LastName   |    FirstName
Hanse      |        Ola
Svendson   |    Tove
Pettersen  |    Kari

如何在不从数据库获取数据的情况下添加自己的列？例如:

SELECT TEST(default: aaa), LastName,FirstName FROM Persons

这应该告诉我:

TEST | LastName   | FirstName
aaa  | Hanse      |        Ola
aaa  | Svendson   | Tove
aaa  | Pettersen  | Kari

Answer 1

SELECT 'aaa' as test, LastName,FirstName FROM Persons