我在oracle DB中有三个表，如下所示：
Training_Calendar_hdr
<html>, <body>Training_Employee_mapping
-----------------------------
Training_Id Training_Name
-----------------------------
T1 Physics
T2 Chemistry
T3 Maths
Employee_Details
---------------------------
Training_Id Employee_Id
---------------------------
T1 E001
T1 E003
T1 E007
T3 E001
T3 E010
T3 E008
T3 E011
我需要通过连接三个表来获得结果，如下所示：
---------------------------
Employee_Id Designation
---------------------------
E001 Engineer
E002 Professor
E003 Businessman
E004 Engineer
E005 Govt. Service
E006 Unemployed
E007 Engineer
E008 Govt. Service
E009 Professor
E010 Unemployed
E011 Professor