For more information about how to use the union result set in SQL study note 6, see.
For more information about how to use the union result set in SQL study note 6, see.
Union result set
Create temporary data table
The Code is as follows:
Create table T_TempEmployee (FIdCardNumber VARCHAR (20), FName VARCHAR (20), FAge int, primary key (FIdCardNumber ));
Insert into T_TempEmployee (FIdCardNumber, FName, FAge) VALUES ('20140901', 'sarani ', 33 );
Insert into T_TempEmployee (FIdCardNumber, FName, FAge) VALUES ('20140901', 'Tom ', 26 );
Insert into T_TempEmployee (FIdCardNumber, FName, FAge) VALUES ('20170101', 'alaha', 38 );
Insert into T_TempEmployee (FIdCardNumber, FName, FAge) VALUES ('20140901', 'tina ', 26 );
Insert into T_TempEmployee (FIdCardNumber, FName, FAge) VALUES ('20140901', 'konkaya', 29 );
Insert into T_TempEmployee (FIdCardNumber, FName, FAge) VALUES ('000000', 'fotifa ', 46 );
Union
The Code is as follows:
Select FNumber, FAge from T_Employee
Union
Select FIdCardNumber, FAge from T_TempEmployee
The number and type of queries on and off the union must be consistent.
The Code is as follows:
Select FNumber, FAge, FDepartment from T_Employee
Union
Select FIdCardNumber, FAge, 'temporary employee, no departments' from T_TempEmployee
Union removes duplicate data by default. If he is not removed, union all is used.
The Code is as follows:
Select FName from T_Employee
Union all
Select FName from T_TempEmployee
