选择所有数据，包括另一个表，即使为null [英] Select all data include another table even if null

问题描述

设置: (1)员工表(employeeID，firstName，lastName)

Setup: (1) Employee table (employeeID, firstName, lastName)

(1)鞋桌(shoeID，Employee_employeeID，shoeName，shoeColor，shoeBrand)

(1) Shoe table (shoeID, Employee_employeeID, shoeName, shoeColor, shoeBrand)

我想选择Employee表中的所有行，即使在热靴表中没有匹配的EmployeeID(Employee_EmployeeID)仍然显示整个行.所需输出示例:

I want to select all rows in Employee table and even if there is no matching EmployeeID (Employee_EmployeeID) in the shoe table display that entire row anyway. Example desired output:

 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

我尝试了很多不同的联接，每个员工都会得到重复的行.

I have tried a lot of different joins and I will get duplicate rows for each Employee.

推荐答案

尝试一下

   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

此处演示SQLFIDDLE

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