MySQL explains how it would process the statement, including information about how tables are joined and in which order. For information about using EXPLAIN to obtain execution plan information, see Section 8.8.2, “EXPLAIN Output Format”. 当...
WHILE i < n DO SET return_str =CONCAT(return_str,SUBSTRING(chars_str,FLOOR(1+RAND()*52),1)); SET i = i + 1; END WHILE; RETURN return_str; END // DELIMITER ; 创建存储过程 创建往s1表中插入数据的存储过程: DELIMITER // CREATE PROCEDURE insert_s1 (IN min_num INT (10),IN max_...
CREATE DEFINER=`root`@`localhost` PROCEDURE `generateBigDataUser`(IN num INT) BEGIN #Routine body goes here... #申明变量i,默认为1 DECLARE i INT DEFAULT 1; #当i小于传入的参数时执行循环插入 WHILE i <= num DO INSERT INTO `big_data_user_memory`(`user_id`, `user_name`, `age`, `gen...
The 'do-while' loop can be implemented (in C) as: inti=5; do { printf("%d",i); i--; }while(i>=0); where 'i' is the loop variable. Answer and Explanation:1 Both for loop and while loop can run multiple statements in successive repetition efficiently. ...
1CREATE DEFINER=`root`@`localhost` PROCEDURE `generateBigDataUser`(IN num INT) 2BEGIN 3 #Routine body goes here... 4 5 #申明变量i,默认为1 6 DECLARE i INT DEFAULT 1; 7 8 #当i小于传入的参数时执行循环插入 9 WHILE i <= num DO ...
一. NESTED LOOP: 对于被连接的数据子集较小的情况,嵌套循环连接是个较好的选择。在嵌套循环中,内表被外表驱动,外表返回的每一行都要在内表中检索找到与它匹配的行,因此整个查询返回的结果集不能太大(大于1 万不适合),要把返回子集较小表的作为外表(CBO 默认外表是驱动表),而且在内表的连接字段上一定要有索...
SUCCESS: RETURN 0 FAIL: RETURN -200 while表达式 while 条件表达式 do 逻辑体; end while; LOOP表达式 LOOP... END LOOP;例: OPEN c1; ins_loop: LOOP FETCH c1 INTO v_dept, v_deptname, v_admdept; IF at_end = 1 THEN LEAVEins_loop; --中断循环 ELSEIF v_dept = 'D11' THEN ITERATEins...
What would happen to the time complexity (Big-O) of the methods in an array implementation of a stack if the top of the stack were at position 0? Explain. Explain array in java. Explain the difference between while loop and for loop? Give an example for the while loop and the for lo...
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For example, when the SQL statement contains bind variables the plan shown from using EXPLAIN PLAN ignores the bind variable values while the plan shown in V$SQL_PLAN takes the bind variable values into account in the plan generation process. It is easy to display an execution plan using the...