SQL進修筆記六 union結合成果集應用

SQL進修筆記六 union結合成果集應用。本站提示廣大學習愛好者：（SQL進修筆記六 union結合成果集應用）文章只能為提供參考，不一定能成為您想要的結果。以下是SQL進修筆記六 union結合成果集應用正文

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結合成果集
新建暫時工數據表

CREATE TABLE T_TempEmployee (FIdCardNumber VARCHAR(20),FName VARCHAR(20),FAge int,PRIMARY KEY(FIdCardNumber));
INSERT INTO T_TempEmployee(FIdCardNumber,FName,FAge) VALUES('1234567890121','Sarani',33);
INSERT INTO T_TempEmployee(FIdCardNumber,FName,FAge) VALUES('1234567890122','Tom',26);
INSERT INTO T_TempEmployee(FIdCardNumber,FName,FAge) VALUES('1234567890123','Yalaha',38);
INSERT INTO T_TempEmployee(FIdCardNumber,FName,FAge) VALUES('1234567890124','Tina',26);
INSERT INTO T_TempEmployee(FIdCardNumber,FName,FAge) VALUES('1234567890125','Konkaya',29);
INSERT INTO T_TempEmployee(FIdCardNumber,FName,FAge) VALUES('1234567890126','Fotifa',46);


Union結合

select FNumber,FAge from T_Employee
union
select FIdCardNumber,FAge from T_TempEmployee


union高低的查詢個數和類型必需對應分歧

select FNumber,FAge,FDepartment from T_Employee
union
select FIdCardNumber,FAge ,'暫時工，無部分' from T_TempEmployee


union默許將反復數據去失落。假如不讓他去失落，則用union all

select FName from T_Employee
union all
select FName from T_TempEmployee