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MySL實(shí)現(xiàn)如等級(jí)成色等特殊順序的排序詳解

更新時(shí)間：2023年05月25日 14:54:46 作者：北橋蘇

這篇文章主要為大家介紹了MySL實(shí)現(xiàn)如等級(jí)成色等特殊順序的排序詳解，有需要的朋友可以借鑒參考下，希望能夠有所幫助，祝大家多多進(jìn)步，早日升職加薪

前言：

在涉及商品類的項(xiàng)目時(shí)，為了給同一類商品定位，往往會(huì)分等級(jí)或者成色。而等級(jí)/成色有時(shí)是用類似A，A+，A+1，K，L1，L2等英文與數(shù)字的組合進(jìn)行表述。既然是等級(jí)，自然就會(huì)區(qū)分高等級(jí)，低等級(jí)。有高有低，又給商品定了等級(jí)，所以到了商品列表展示，等級(jí)排序自然少不了。

項(xiàng)目在開始做的時(shí)候關(guān)于商品等級(jí)字段是直接存儲(chǔ)的上面的字母數(shù)字，也就是A，A+1之類的。所以在需要以等級(jí)排序的時(shí)候，以英文字母的方式升序倒序就出現(xiàn)了問題，比如大部分等級(jí)中，S是最高級(jí)，而英文倒序S排在了后面。

沖突：

直接以英文字母排序很顯然是不行的，于是首先想到的是數(shù)據(jù)表的等級(jí)字段改為int，存入數(shù)字。在配置里或者單獨(dú)建一張表與對(duì)應(yīng)數(shù)字關(guān)聯(lián)一個(gè)等級(jí)。類似K對(duì)應(yīng)1之類的，需要升序降序就對(duì)數(shù)字排序，這樣就解決了S排序問題。但是，現(xiàn)實(shí)的是商品表的數(shù)據(jù)量極大，如果要給原來的等級(jí)做關(guān)聯(lián)，就要小心的寫SQL替換或者手動(dòng)一個(gè)一個(gè)改。不知道有沒有在不需要修改表的情況下解決那種特殊字符排序的方法，后來還真想到了一個(gè)方法。

解決方法：

通過使用MySQL的find_in_set函數(shù)，通過自定義的順序進(jìn)行排序，所以后續(xù)將某個(gè)等級(jí)提前改動(dòng)都不會(huì)那么被動(dòng)了，如下示例。

1. 可以先定義升序，倒序的排列

"grade_desc" => ["S","A+","A1","A2","B+1","B+2","B1","B2","C+1","C+2","C1","C2","D+1","D+2","D1","D2","D3","E+1","E+2","E1","E2","F","G+","G1","G2","H+","H1","H2","I+","I1","I2","J+","J","K+","K"]"grade_asc" => ["K","K+","J","J+","I2","I1","I+","H2","H1","H+","G2","G1","G+","F","E2","E1","E+2","E+1","D3","D2","D1","D+2","D+1","C2","C1","C+2","C+1","B2","B1","B+2","B+1","A2","A1","A+","S"]

2. 查詢示例

3. ThinkPHP5的使用方式

3.1. 升序

$list = GoodsItem::where('delete_time','=',0)
            ->field('id,grade')
            ->orderRaw("find_in_set(grade,'K,K+,J,J+,I2,I1,I+,H2,H1,H+,G2,G1,G+,F,E2,E1,E+2,E+1,D3,D2,D1,D+2,D+1,C2,C1,C+2,C+1,B2,B1,B+2,B+1,A2,A1,A+,S')")
            ->select();
return $list->toArray();

3.2. 倒序

$list = GoodsItem::where('delete_time','=',0)
            ->field('id,grade')
            ->orderRaw("find_in_set(grade,'S,A+,A1,A2,B+1,B+2,B1,B2,C+1,C+2,C1,C2,D+1,D+2,D1,D2,D3,E+1,E+2,E1,E2,F,G+,G1,G2,H+,H1,H2,I+,I1,I2,J+,J,K+,K')")
            ->select();
        return $list->toArray();

3.3.效果