mysql - 选择所有数据包括另一个表，即使为空

Question

设置: (1) Employee表(employeeID、firstName、lastName)

(1) 鞋表(shoeID、Employee_employeeID、shoeName、shoeColor、shoeBrand)

我想选择 Employee 表中的所有行，即使鞋表中没有匹配的 EmployeeID (Employee_EmployeeID) 也会显示整行。所需输出示例:

 EmployeeID  | firstName    | lastName    | shoeName     |   shoeColor  | shoeBrand

 1            John           Smith         AirMax2          Red          Nike
 2            Ronald         Mcdonald      null             null         null
 3            James          Knight        null             null         null
 4            Cindy          Smith         Pump             Brown        Cole Haan

我已经尝试了很多不同的连接，我会得到每个员工的重复行。

Answer 1

试试这个

   SELECT e.employeeId,e.firstName,e.lastName,s.ShoeName,s.ShoeColor,s.ShoeBrand 
   FROM    Employee e
   LEFT JOIN Shoe s
   ON e.employeeID = s.Employee_employeeID

DEMO SQLFIDDLE HERE