Question

我尝试执行一个过程以从另一个表填充一个表。

但是在调用该过程时，此表将在另一个表中填充为空。

过程如下：

DELIMITER //
CREATE PROCEDURE invent()
BEGIN
    DECLARE bDone INT;

    DECLARE hostname VARCHAR(100);

    DECLARE curs CURSOR FOR  
        select hostname from GetInvent;

    DECLARE CONTINUE HANDLER FOR NOT FOUND SET bDone = 1;
    DROP TABLE Persons;

    CREATE TABLE Persons (
        `id` int(11) NOT NULL AUTO_INCREMENT,
        `hostname` VARCHAR(100),
        PRIMARY KEY (`id`)
    );

    SET bDone = 0;
    OPEN curs;
    igmLoop: loop
        FETCH curs INTO hostname;

        if bDone = 1 then leave igmLoop; end if;

        INSERT INTO Persons(hostname) VALUES (hostname);

    END LOOP igmLoop;

    CLOSE curs;

    SELECT * FROM Persons;
END //
DELIMITER ;

在GetInvent中大约有50.000条记录了循环工作，因为在Persons表中，调用该过程后，主机名等于Null，我得到了大约50.000条

有什么主意吗？

Answer 1

我在这里找到了问题的答案：MySQL cursor fetch NULL

错误是变量名，属性主机名的名称不能相同。

修复过程：

DELIMITER //
CREATE PROCEDURE invent()
BEGIN
DECLARE bDone INT;

DECLARE v_hostname VARCHAR(100);

DECLARE curs CURSOR FOR  
    select hostname from GetInvent;

DECLARE CONTINUE HANDLER FOR NOT FOUND SET bDone = 1;
DROP TABLE Persons;

CREATE TABLE Persons (
    `id` int(11) NOT NULL AUTO_INCREMENT,
    `hostname` VARCHAR(100),
    PRIMARY KEY (`id`)
);

SET bDone = 0;
OPEN curs;
igmLoop: loop
    FETCH curs INTO v_hostname;

    if bDone = 1 then leave igmLoop; end if;

    select v_hostname;

    INSERT INTO Persons(hostname) VALUES (v_hostname);

END LOOP igmLoop;

CLOSE curs;

SELECT * FROM Persons;
END //
DELIMITER ;

Mysql填充表的过程，游标获取null

1 个答案: