The time taken by the fast forward cursor to complete the operation is 8 seconds. Converting Cursor to While Loop Now, let us convert the above example toWHILE loop. To convert a cursor to while loop, first you
In some scenarios, if there's a primary key on a table, aWHILEloop can be used instead of a cursor, without incurring in the overhead of a cursor. However, there are scenarios where cursors aren't only unavoidable, they're actually needed. When that is the case, if there's no requi...
SELECT CONCAT(first_name,'2') FROM stu;-- 当fetch游标到了数据库表格最后一行的时候,设置done=1。 DECLARE CONTINUE HANDLER FOR SQLSTATE'02000'SET done=1;--错误标记处理,放到最后再声明,要放到游标后面。--不然会报错:Variable or condition declaration after cursor or handler declaration DECLARE CONTINUE...
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、...
Daniel Farina wrote an interesting article (SQL Server Loop through Table Rows without Cursor) comparing the SQL Server While Loop and Cursors. He covers the following: Using a While Loop Instead of Cursors in SQL Server Pros and Cons of Using Cursors to Iterate Through Table Rows in SQL Serv...
fetch[cursor变量]into[循环变量] 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...
13. open cursor_part; 14. loop 15. fetch cursor_part into cursor_oldpart; 16. exit when cursor_part%notfound; 17. v_sqlexec:='ALTER TABLE SVRSENSORDATA DROP PARTITION '||cursor_oldpart.partition_name; 18. DBMS_Utility.Exec_DDL_Statement(v_SqlExec); ...
AvgPageDensityINT, ScanDensityDECIMAL, BestCountINT, ActualCountINT, LogicalFragDECIMAL, ExtentFragDECIMAL);-- Open the cursor.OPEN tables;-- Loop through all the tables in the database.FETCH NEXT FROM tables INTO @tablename; WHILE @@FETCH_STATUS = 0BEGIN-- Do the showcontig of all indexes...
SQL Server 2017 adjusts memory grants based on execution feedback, removes spills to disk, and improves concurrency for repeating queries. Batch mode adaptive joins Adaptive joins dynamically select a better internal join type (nested loop joins, merge joins or hash joins) during ...
Added an option for enclaveAttestationProtocol Added option for NONE protocol so that secure enclaves can be used without attestation. Allow serverName to be reordered in connection string Validate that the serverName field of the connection string doesn't have an equal sign. Added better error log...