MySQL

Question

我正在创建一个包含删除语句和游标用法的存储过程。问题是我不能同时使用这两个。

这是一个独立的 MWE。注意Block 1和Block 2可以分开运行（如果我评论另一个），但不能一起

drop table if exists T1;
create table T1(f1 int, f2 int);
insert into T1 values(1, 1);
insert into T1 values(2, 2);
insert into T1 values(3, 3);

drop table if exists T2;
create table T2(f3 int, f4 int);
insert into T2 values(1, 11);
insert into T2 values(2, 22);
insert into T2 values(3, 33);


drop procedure if exists proc1;
DELIMITER //
CREATE PROCEDURE proc1(inputValue int)
    BEGIN
    declare i int;
    declare cursorSize int;
    declare anF1 int;
    declare anF2 int;

    -- Block 1 - Begin:    
    delete from T2 where f3 = inputValue;
    -- Block 1 - End.    
    
    -- Block 2 - Begin:    
    declare cur1 cursor for 
        select f1, f2  
            from T1
            where f1 <= inputValue;
    open cur1;

    select FOUND_ROWS() into cursorSize;
    if (cursorSize > 0) then
        set i = 0;
        while i < cursorSize DO
            fetch cur1 into anF1, anF2;
                insert into T2 values(anF1, anF2);
            set i = i + 1;
            end while;
        end if;

    close cur1;
    -- Block 2 - End.    
    
    END //
DELIMITER ;

call proc1(3);

如果我取消注释块 1 中的删除语句，我会收到此错误：

1064 - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near
    'declare cur1 cursor for 
    select f1, f2  
        from T1
        where f1 <=' at line 10

请帮我解决问题。

Answer 1

文档似乎没有明确说明，但我相当确定在游标声明之前不能有任何查询。

您应该能够在声明 CURSOR 之后但在打开之前执行该 DELETE。

MySQL - 在带游标的存储过程中删除

MySQL - delete in stored procedure with cursor

stored-procedures

cursor

sql-delete

1064 - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near