如何使用字符串和int值

您好我有這個下表..如何使用字符串和int值

offer_number  training_title 
************** 
    ABC-1   SEMINAR 
    ABC-9   SEMINAR 
    ABC-10   SEMINAR 
    ABCD-9   TRAINING 
    EFGH-9   TESTING 
    EFGH-10  TESTING

Mysql的

SELECT *, MAX(offer_number) as offer_number_latest FROM (`training_program`) WHERE `training_title` LIKE '%SEMINAR%' GROUP BY `training_title` ORDER BY `offer_number` desc

我想製作ABC-10 但我總是得到ABC-選擇馬克斯9而不是ABC-10。

示例2：

SELECT *, MAX(offer_number) as offer_number_latest FROM (`training_program`) WHERE `training_title` LIKE '%TESTING%' GROUP BY `training_title` ORDER BY `offer_number` desc

我需要的結果EFGH-10 但我總是EFGH-9不是EFGH-10。

來源

2015-05-25 freddy

9> 1 - 你就必須有「ABC-09」進行比較，以工作的方式..相反，你可以「提取」從字符串的數量和使用 - 簡單的應該是「REPLACE（offer_number ，'ABC-'，''）「只獲取字符串的數字部分（[或使用udf正則表達式？]（http://stackoverflow.com/a/986870/1786423）），然後您可能必須CAST（）表示數字（或加上+0使用自動轉換） – jkavalik

是字符前綴總是每組相同？ –

freddy？上面的任何輸入？ –

如果offer_number前綴始終是每training_title相同，下面的（骯髒）的查詢將工作：

select training_title, 
    concat(
    left(offer_number, 
     locate('-', offer_number) 
    ), 
    max(
     cast(substring(offer_number, locate('-', offer_number) + 1) as signed) 
    ) 
) from offers group by training_title

demo here

來源

2015-05-25 07:34:26

-1

MySQL也有字符串函數。

mysql> select * from offer; 
    +--------------+----------------+ 
    | offer_number | training_title | 
    +--------------+----------------+ 
    | ABC-1  | SEMINAR  | 
    | ABC-9  | SEMINAR  | 
    | ABC-10  | SEMINAR  | 
    | ABC-8  | SEMINAR  | 
    | ABC-14  | SEMINAR  | 
    | ABC-12  | SEMINAR  | 
    +--------------+----------------+ 
    6 rows in set (0.00 sec) 

    mysql> SELECT MAX(CAST(SUBSTRING(offer_number,LOCATE('-',offer_number)+1) AS SIGNED)) as MAX FROM offer ; 
    +------+ 
    | MAX | 
    +------+ 
    | 14 | 
    +------+ 
    1 row in set (0.00 sec) 

    mysql> SELECT * FROM offer ORDER BY CAST(SUBSTRING(offer_number,LOCATE('-',offer_number)+1) AS SIGNED); 
    +--------------+----------------+ 
    | offer_number | training_title | 
    +--------------+----------------+ 
    | ABC-1  | SEMINAR  | 
    | ABC-8  | SEMINAR  | 
    | ABC-9  | SEMINAR  | 
    | ABC-10  | SEMINAR  | 
    | ABC-12  | SEMINAR  | 
    | ABC-14  | SEMINAR  | 
    +--------------+----------------+ 
    6 rows in set (0.00 sec)

來源

2015-05-25 08:56:59 manoj

如何使用字符串和int值

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