mysql - DECLARE CURSOR FOR 语法错误

Question

我不明白为什么我在下面的 sp 代码中出现语法错误。谁能帮我解决这个问题？

SQL 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 pc.prospectus_courses_id FROM prereq_cou' at line 8

DELIMITER $$
DROP PROCEDURE IF EXISTS get_prereqs3$$
CREATE PROCEDURE get_prereqs3(IN prosp_courses_id SMALLINT(5))
BEGIN
    DECLARE done  int DEFAULT FALSE;
    DECLARE required SMALLINT(5) default 0; 
    DECLARE to_search SMALLINT(5) default 0; 
    DROP TABLE IF EXISTS tmp_list;
    CREATE TABLE tmp_list(courses_id SMALLINT(5), courses_id_req SMALLINT(5)) ENGINE = MEMORY;
    DECLARE CUR1 CURSOR FOR SELECT pc.prospectus_courses_id 
            FROM prereq_courses     pc          
            JOIN prerequisites      pr on (pr.id = pc.prerequisites_id)
            JOIN prospectus_courses ps on (ps.id = pr.prospectus_courses_id)
            WHERE ps.id = to_search 
    MAIN_LOOP: LOOP 
        DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;
        OPEN cur1;
        FETCH cur1 INTO required;

        IF done THEN
            CLOSE cur1;
            LEAVE main_loop;
        ELSE
            insert into tmp_list values (to_search, required);
            set to_search = required;
            iterate main_loop;
        END IF;
    END LOOP;
    select  c.course_code 
        from tmp_list           t
        join prospectus_courses pc on pc.id = t.courses_id_req
        join courses            c  on c.id  = pc.courses_id ;
    drop table tmp_list;
END$$
DELIMITER ;

Answer 1

声明必须紧跟在 BEGIN block 之后。在您的情况下，只需移动 DECLARE cur1 CURSOR 和 DECLARE CONTINUE HANDLER.. 两行。

有时您希望稍后在代码中声明变量或游标，例如，如果满足条件。

在这种情况下，您可以再次用嵌套的 BEGIN .. END 包裹该 block 。

http://dev.mysql.com/doc/refman/5.5/en/begin-end.html和 http://dev.mysql.com/doc/refman/5.5/en/declare.html

DECLARE is permitted only inside a BEGIN ... END compound statement and must be at its start, before any other statements.

您还声明了 CUR1 但使用的是 cur1。