DECLARE done INT DEFAULT FALSE; DECLARE example_data VARCHAR(255); DECLARE cur CURSOR FOR SELECT column_name FROM your_table; DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE; -- 打开游标 OPEN cur; -- 循环遍历结果集 read_loop: LOOP FETCH cur INTO example_data; IF done THEN LEAVE ...
6. 关闭 Cursor 一旦操作完成,Cursor 会在存储过程的最后通过CLOSE语句自动关闭。确保在使用完 Cursor 后进行关闭是良好的编程习惯。 流程图 使用以下 Mermaid 语法来展示整个流程的图形化表示: 创建数据库创建表插入数据定义 Cursor使用 Cursor关闭 Cursor 状态图 使用以下 Mermaid 语法可以表示状态处理的流程: 完成未...
DELIMITER//CREATEPROCEDUREexample_cursor()BEGINDECLAREdoneINTDEFAULTFALSE;DECLAREemp_nameVARCHAR(100);DECLAREemp_positionVARCHAR(100);DECLAREcursor_employeeCURSORFORSELECTname,positionFROMemployees;DECLARECONTINUEHANDLERFORNOTFOUNDSETdone=TRUE;OPENcursor_employee;read_loop:LOOPFETCHcursor_employeeINTOemp_name,emp_...
Wherefinishedis a variable to indicate that the cursor has reached the end of the result set. Notice that the handler declaration must appear after variable and cursor declaration inside the stored procedures. The following diagram illustrates how MySQL cursor works. MySQL Cursor Example We are goin...
Example #2Source File: map-string-ids.py From dipper with BSD 3-Clause "New" or "Revised" License 6 votes def get_xref_protein_gene_rel(cursor: Cursor, protein: str, database: str, config: dict, taxon: str) -> str: select_database(cursor, database) find_gene_query = \ config...
student_cursor; -- 循环处理 read_loop: LOOP FETCH student_cursor INTO s_id, s_name; IF done THEN LEAVE read_loop; END IF; -- 为新生创建初始记录 INSERT INTO student_records (student_id, status) VALUES (s_id, 'active'); END LOOP; -- 关闭游标 CLOSE student_cursor; -- 提交事务 ...
#Cursor close语句用来关闭之前打开的游标 如果关闭一个未打开的游标,则MySQL会报错 如果在存储过程和函数中未使用此语句关闭已经打开的游标,则游标会在声明的begin…end语句块执行完之后自动关闭 #Cursor declare语句用来声明一个游标和指定游标对应的数据集合,通常数据集合是一个select语句 #Cursor fetch语句用来获取游标...
MySQL Cursor Example We are going to develop a stored procedure that builds an email list of all employees in theemployeestable in the MySQL sample database. First, we declare some variables, a cursor for looping over the emails of employees, and aNOT FOUNDhandler: ...
Example Use Case Let us create a cursor that collects customers’ emails available in the customer table of the Sakila sample database. The resource for downloading and installing the Sakila database is below: https://dev.mysql.com/doc/sakila/en/ ...
CLOSE my_cursor; RETURN SUBSTR(stu_list,3); END // DELIMITER ; SELECT student_list() AS Cities; DROP FUNCTION student_list; 4:output 参考:http://www.roseindia.net/sql/mysql-example/mySQL-cursor.shtml http://dev.mysql.com/doc/refman/5.0/en/cursors.html...