Again, it really depends on your situation. I almost always use a cursor to loop through records...
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 t...
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、...
参考示例:https://blog.csdn.net/xw1680/article/details/130119856 DELIMITER $$ DROP PROCEDURE IF EXISTS `sp_cursor_test3` $$ CREATE PROCEDURE `sp_cursor_tes
The WHILE loop, according toSQL Server Loop through Table Rows without Cursorarticle, states that a WHILE is faster than a cursor and uses less locks and use less TEMPDB resources. However, WHILE loops are still slow and have a performance impact. If it is a nested loop, it will be even...
Use the "Checklist: SQL Server Performance" checklist to quickly view and evaluate the guidelines presented in this chapter.SQL: Scale Up vs. Scale OutScaling up refers to moving an application to a larger class of hardware that uses more powerful processors, more memory, and quicker disk ...
(),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 partition...
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...
Use the "Checklist: SQL Server Performance" checklist to quickly view and evaluate the guidelines presented in this chapter.SQL: Scale Up vs. Scale OutScaling up refers to moving an application to a larger class of hardware that uses more powerful processors, more memory, and quicker disk ...
(),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.WHILE (1 = 1)BEGIN; FETCH...