ORACLE和DB2支持的大對象是什么?MS SQL支持的大對象是什么?

在MS SQL中image數據類型的存儲容量是多少?

在MS SQL中varbinary數據類型的存儲容量是多少?

編寫查詢,按條件合并兩列為一列(i.e.我想從FullName或FirstName的列中找出不為空的雇員的名字)。

如何使用查詢創建標識列?

哪個函數可以用來比較兩個不同的日期?

查找超過40歲的所有員工。

編寫查詢,從EMPLOYEE表中找到第二高薪水的員工。

編寫查詢,不使用JOIN操作符,從EMPLOYEE表中查找名字開頭是“s”和居住在城市“Mumbai”的所有員工。

如何從EMPLOYEE表中刪除重復的員工條目?

Oracle和DB2是BLOB(Binary Large Objects),CLOB(Character Large Objects)。MS SQL是image和varbinary。

最大為2G的可變長度的二進制數據。

最大為8000字節的可變長度的二進制數據。

SELECT Name = CASE

WHEN EMPLOYEE.FullName IS NOT NULL THEN EMPLOYEE.FullName

WHEN EMPLOYEE.FirstName IS NOT NULL THEN EMPLOYEE.FirstName

END

FROM EMPLOYEE

SELECT row_number() OVER(ORDER by TESTTABLE.p1) as SRNO,

result = CASE

WHEN TESTTABLE.p1 IS NOT NULL THEN TESTTABLE.p1

WHEN TESTTABLE.p2 IS NOT NULL THEN TESTTABLE.p2

END

FROM TESTTABLE

SELECT DATEDIFF(dd,'10‐10‐2017','15‐10‐2017');

SELECT COUNT(EMPLOYEES.*) FROM EMPLOYEES WHERE EMPLOYEES.Age>40

SELECT EMPLOYEE.*, MAX(EMPLOYEE.Salary) AS SalarySecondHighest

FROM EMPLOYEE

WHERE EMPLOYEE.Salary <

(SELECT MAX(EMPLOYEE.Salary) AS SalaryFirstHighest FROM EMPLOYEE)

SELECT EMPLOYEE.* FROM EMPLOYEE

WHERE CHARINDEX('s',EMPLOYEE.name) = 1 AND

CHARINDEX('Mumbai',EMPLOYEE.City) > 0

第一步,選擇重復的員工記錄并將其復制到holdTable表中:

SELECT EMPLOYEE.EmployeeID, COUNT(EMPLOYEE.EmployeeID), *

INTO HoldTable

FROM EMPLOYEE

GROUP BY EMPLOYEE.EmployeeID

HAVING COUNT(EMPLOYEE.EmployeeID) > 1

第二步,選擇重復的行到另一個HoldDistinct表中:

SELECT DISTINCT EMPLOYEE.*

INTO HoldDistinct

FROM EMPLOYEE, HoldTable

WHERE EMPLOYEE.EmployeeID=HoldTable.EmployeeID

第三步,從EMPLOYEE表中刪除重復行:

DELETE EMPLOYEE

FROM EMPLOYEE, HoldTable

WHERE EMPLOYEE.EmployeeID = HoldTable.EmployeeID

第四步,插于不同條目:

INSERT INTO EMPLOYEE(EmployeeID, FirstName, LastName, Salary, ...otherlist of columns)

SELECT EmployeeID, FirstName, LastName, Salary, ...other list of columns)

FROM HoldDistinct