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...
You would use aCURSOR FOR Loopwhen you want to fetch and process every record in a cursor. TheCURSOR FOR Loopwill terminate when all of the records in the cursor have been fetched. 译:当你每次想通过cursor来对每条记录进行取及操作时,就可以使用CURSOR FOR Loop。当cursor中所有的记录都取后,CUR...
IF(done = 0) THEN -- 处理FETCH到的数据 SET msg = CONCAT(msg,fname,'/'); ELSE -- 关闭游标 CLOSE cs1; -- 跳出循环标记 LEAVE read_loop; END IF; -- 结束标记,在循环体中判断并跳出。 END LOOP; -- 关闭游标 CLOSE cs1; -- 游标2 OPEN cs2; SET done = 0; -- REPEAT循环 REPEAT -...
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...
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:
-row. You might have used CURSORs to perform such tow-by-row operations. However, I do not prefer to use cursors as they are slow and will impact performance. As a good practice I always try not to use cursors in my sql code. But, how to loop through table rows without a cursor?
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EXEC SQL DECLARE C1 CURSOR FOR S1; EXEC SQL OPEN C1 USING :person_no; printf("The resultis:%s\n",person_no); EXEC SQL FETCH C1 INTO :person_name,:person_phone; printf("NO=%s,NAME=%s\n\n",person_phone, person_name); EXEC SQL CLOSE C1; EXEC SQL DROP TABLE PERSON CASCADE; sql...
In this example, the SELECT statement of the cursor retrieves data from the products table. The FOR LOOP statement opened, fetched each row in the result set, displayed the product information, and closed the cursor. 2) Cursor FOR LOOP with a SELECT statement example The following example ...
END LOOP; emp_refcur := test_cursor; CLOSE test_cursor; END; 然后调用此过程,向其传递一个类型的SYS_REFCURSOR变量以检索游标: DECLARE emp_cur SYS_REFCURSOR; BEGIN p_close_refcursor(emp_cur); END; 尝试在 SSMA 中转换前面的代码时,它会生成以下错误消息: ...