查询emp中所有工资大于等于2000元的雇员姓名和他领导的姓名

为了查询`emp`表中所有工资大于等于2000元的雇员及其直接领导的姓名，我们需要假设存在一个`Manager`表或者通过`emp`表的`ManagerId`字段关联了每个员工的上级经理。查询可以分为两部分：

1. 获取工资大于等于2000的员工列表，包括他们的姓名：

   SELECT e.Name AS EmployeeName
   FROM emp e
   WHERE e.Salary >= 2000;

2. 然后基于员工的`ManagerId`查找他们的直接领导（假设`Manager.Id`为领导的唯一标识符）：

   SELECT m.Name AS ManagerName
   FROM emp e
   JOIN Manager m ON e.ManagerId = m.Id
   WHERE e.Salary >= 2000;

最后，如果需要同时列出这两个结果，你可以将两个查询结合起来：

WITH HighPaidEmployees AS (
  SELECT e.Name AS EmployeeName
  FROM emp e
  WHERE e.Salary >= 2000
),
Leaders AS (
  SELECT m.Name AS ManagerName
  FROM emp e
  JOIN Manager m ON e.ManagerId = m.Id
  WHERE e.Name IN (SELECT Name FROM HighPaidEmployees)
)
SELECT * FROM HighPaidEmployees
UNION ALL
SELECT * FROM Leaders
ORDER BY EmployeeName;