while_label: WHILE i<=50DO SET s= s +i; SET i= i +1; END WHILE while_label; SET num=s; END%%DELIMITER ; CALL test_while(@x); SELECT @x; 跳转语句之ITERATE语句 ITERATE语句:只能用在循环语句(LOOP、REPEAT和WHILE语句)内,表示重新开始循环,将执行顺序转到语句段开头处。如果你有面向过程的编程语言的使用经验,你可以把 ITERATE ...
While SQL While loop is quicker than a cursor, reason found that cursor is defined by DECLARE CURSOR. Every emphasis of the loop will be executed inside system memory and consuming required server assets. On the off chance that the iteration count is extremely high, at...
Creating a SQL Server cursor with T-SQL is a consistent method that can process data on a set of rows. Once you learn the steps, you can easily duplicate them with various sets of logic to loop through data. Let’s walk through the steps: Declare Variables Declare the variables (file n...
Similarly, the cursor FOR LOOP executes the body of the loop once for each row returned by the query associated with the cursor. A nice feature of the cursor FOR LOOP statement is that it allows you to fetch every row from a cursor without manually managing the execution cycle i.e., ...
when[cursor变量]%notfound; 例子: loop fetchdomainNamesintodomainName; exitwhendomainNames%notfound; end loop; 3、if使用 if(条件)then [真值语句块] end if; 4、单引号字符表示 ''':最外层两个单引号表示字符串引用,字符串中间第一个单引号表示转义,第二个单引号表示单引号。 例子...
游标Cursor逻辑运算符和物理运算符用于描述涉及游标操作的查询或更新的执行方式。 其中物理运算符描述用于处理游标(如使用键集驱动游标)的物理实现算法。 游标执行过程的每一步都涉及物理运算符。 而逻辑运算符描述游标的属性,如游标是只读。 逻辑运算符包括Asynchronous、Optimistic、Primary、Read Only、Scroll Locks、Seco...
This Oracle tutorial explains how to use the CURSOR FOR LOOP in Oracle with syntax and examples. The syntax for the CURSOR FOR Loop in Oracle / PLSQL is:
Now, let us convert the above example toWHILE loop. To convert a cursor to while loop, first you have to find the total number of rows in the table. Then you have to iterate through the table rows using WHILE control-of-flow element till the total row count is reached. Here is how...
First, let’s create some sample tables and data for the cursor examples. CREATETABLE[dbo].[Employees]([Id][int]NULL,[Firstname][varchar](50)NULL,[Lastname][varchar](50)NULL,[Phone][varchar](50)NULL,[Email][varchar](50)NULL,[CountryId][varchar](50)NULL,[Dateofbirth][date]NULL,[De...
(),NULL,NULL,NULL,'LIMITED')WHEREavg_fragmentation_in_percent >10.0ANDindex_id >0;-- Declare the cursor for the list of partitions to be processed.DECLAREpartitionsCURSORFORSELECT*FROM#work_to_do;-- Open the cursor.OPEN partitions;-- Loop through the partitions...