MySQL：重复插入到表中

给定一个图书编号id和图书份数，我希望在表中插入与图书份数相同的行数。这是我的非工作解决方案：

DROP PROCEDURE IF EXISTS insert_into_book_copy_table;
CREATE PROCEDURE insert_into_book_copy_table (IN in_book_id INT,
                                              IN in_num     INT)
BEGIN

    SET @I = 1;
    SET @ACQUIRED = CURRENT_TIMESTAMP;

    WHILE I <= in_num DO 
        INSERT INTO book_copy (book_id, acquired) # The table has an
        VALUES (in_book_id, @ACQUIRED);           # auto-increment field
                                                  # which I didn't list here
        SET @I = @I + 1;
    END WHILE;

END$$

---

还有更好的编码方法吗？

试试这个，作为一条SQL语句：-

INSERT INTO book_copy (book_id, acquired)
SELECT a.i+b.i*10+c.i*100 + 1, $BookId, NOW()
FROM integers a, integers b, integers c
WHERE a.i+b.i*10+c.i*100 < $NumberToInsert

插入书本副本（书本id，已获取）
选择a.i+b.i*10+c.i*100+1，$BookId，NOW（）
从整数a，整数b，整数c
其中a.i+b.i*10+c.i*100<$NumberToInsert

依赖于一个整数表，该表有一个10行的单列（称为i），值为0到9。将其自身连接两次可以得到从0到999的所有数字（可以很容易地扩展），因此可以在一个语句中插入多达1000本书

编辑-如果不想创建整数表，则可以对返回常量的两个子查询执行相同的操作：-

INSERT INTO book_copy (book_id, acquired)
SELECT a.i+b.i*10+c.i*100 + 1, $BookId, NOW()
FROM (SELECT 0 AS i UNION SELECT 1 AS i UNION SELECT 2 AS i UNION SELECT 3 AS i UNION SELECT 4 AS i UNION SELECT 5 AS i UNION SELECT 6 AS i UNION SELECT 7 AS i UNION SELECT 8 AS i UNION SELECT 9 AS i ) a,
(SELECT 0 AS i UNION SELECT 1 AS i UNION SELECT 2 AS i UNION SELECT 3 AS i UNION SELECT 4 AS i UNION SELECT 5 AS i UNION SELECT 6 AS i UNION SELECT 7 AS i UNION SELECT 8 AS i UNION SELECT 9 AS i ) b,
(SELECT 0 AS i UNION SELECT 1 AS i UNION SELECT 2 AS i UNION SELECT 3 AS i UNION SELECT 4 AS i UNION SELECT 5 AS i UNION SELECT 6 AS i UNION SELECT 7 AS i UNION SELECT 8 AS i UNION SELECT 9 AS i ) c
WHERE a.i+b.i*10+c.i*100 < $NumberToInsert

插入书本副本（书本id，已获取）
选择a.i+b.i*10+c.i*100+1，$BookId，NOW（）
从（选择0作为i联合选择1作为i联合选择2作为i联合选择3作为i联合选择4作为i联合选择5作为i联合选择6作为i联合选择7作为i联合选择8作为i联合选择9作为i）a，
（选择0作为i联合选择1作为i联合选择2作为i联合选择3作为i联合选择4作为i联合选择5作为i联合选择6作为i联合选择7作为i联合选择8作为i联合选择9作为i）b，
（选择0作为i联合选择1作为i联合选择2作为i联合选择3作为i联合选择4作为i联合选择5作为i联合选择6作为i联合选择7作为i联合选择8作为i联合选择9作为i）c
其中a.i+b.i*10+c.i*100<$NumberToInsert

您会遇到什么错误？打字错误？而我，哦，是的，就是这样。我忽略了I。但是你认为这是一种很好的编码方式吗？

INSERT INTO book_copy (book_id, acquired)
SELECT a.i+b.i*10+c.i*100 + 1, $BookId, NOW()
FROM (SELECT 0 AS i UNION SELECT 1 AS i UNION SELECT 2 AS i UNION SELECT 3 AS i UNION SELECT 4 AS i UNION SELECT 5 AS i UNION SELECT 6 AS i UNION SELECT 7 AS i UNION SELECT 8 AS i UNION SELECT 9 AS i ) a,
(SELECT 0 AS i UNION SELECT 1 AS i UNION SELECT 2 AS i UNION SELECT 3 AS i UNION SELECT 4 AS i UNION SELECT 5 AS i UNION SELECT 6 AS i UNION SELECT 7 AS i UNION SELECT 8 AS i UNION SELECT 9 AS i ) b,
(SELECT 0 AS i UNION SELECT 1 AS i UNION SELECT 2 AS i UNION SELECT 3 AS i UNION SELECT 4 AS i UNION SELECT 5 AS i UNION SELECT 6 AS i UNION SELECT 7 AS i UNION SELECT 8 AS i UNION SELECT 9 AS i ) c
WHERE a.i+b.i*10+c.i*100 < $NumberToInsert