How to use SQL Server Tour banner sentences:
Copy Code code as follows:
--Declares a cursor
DECLARE MyCursor CURSOR
For the SELECT Top 5 fbookname,fbookcoding The from tbookinfo//defines a cursor called MyCursor that holds the data after the for select
--Open a cursor
Open mycursor//Opens the dataset
--Loop a cursor
DECLARE @BookName nvarchar, @BookCoding nvarchar (2000)
Fetch NEXT from MyCursor into @BookName, @BookCoding//move cursor to point to the first data, extract the first data to be stored in the variable
While @ @FETCH_STATUS =0//continue looping if the last operation succeeds
BEGIN
print ' name ' + @BookName
FETCH next from MyCursor into @BookName, @BookCoding//Continue with the next line
End
--Close cursor
Close MyCursor
--Releasing resources
Deallocate mycursor
eg
Copy Code code as follows:
CREATE TABLE #a
(
ID varchar (20),
Name varchar (20)
)
INSERT INTO #a Select 1, ' Jack '
INSERT INTO #a Select 2, ' Join '
Insert INTO #a Select 3, ' Make '
DECLARE mycursor cursor
For a SELECT * from #a
Open MyCursor
DECLARE @id varchar (@name), varchar (20)
FETCH NEXT from MyCursor into @id, @name
While @ @fetch_status =0
Begin
Select @id, @name
FETCH NEXT from MyCursor into @id, @name
End
Close MyCursor
Deallocate mycursor
Cursor is a row-level operation consumes a lot of SQL queries are based on datasets, so general queries can use datasets to use data sets do not use cursors data volume is a performance killer
