如何在mysql中通過小寫字母獲取首字母等數據？

Question

mysql的新手，

我有一張這樣的桌子。

___|____
Id           |    name
1            |       a
2            |       b
3            |       c
4            |       A
5            |       B
6            |       C

---

在sql中獲取這樣的結果的查詢將是什么

___|____
Id           |    name
4            |       A
1            |       a
5            |       B
2            |       b
6            |       C
3            |       c

Answer 1

已編輯

這似乎是將DDS想法轉變為適用於所有MySQL版本的更通用的最簡單方法。

詢問

SELECT 
   id
 , name
FROM 
 Table1
ORDER BY 
  CASE
    WHEN name COLLATE latin1_bin BETWEEN 'A' AND 'Z'
    THEN ASCII(name) + 31
    ELSE ASCII(name)
   END

結果

| id  | name |
| --- | ---- |
| 4   | A    |
| 1   | a    |
| 5   | B    |
| 2   | b    |
| 6   | C    |
| 3   | c    |

在數據庫小提琴上查看

解釋視圖，以便您可以看到DB Fiddle發生的情況

或更穩定的一種，因為為calculated_ascii_value列生成的唯一值。 解釋視圖，以便您可以看到DB Fiddle發生的情況

另一個查詢非常復雜。

詢問

SELECT 
    Table1.id
  , Table1.name 
FROM (

SELECT 
 DISTINCT
   (
     SUBSTRING_INDEX(SUBSTRING_INDEX(@orderList, ',', number_generator.number), ',', -1)
     COLLATE utf8mb4_bin
   ) AS letter
FROM (

SELECT
 (@number := @number + 1) AS number
FROM (
 SELECT 1 AS number UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9 UNION SELECT 10
) AS row_1
CROSS JOIN (
 SELECT 1 AS number UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6
) AS row_2
CROSS JOIN (SELECT @number := 0) AS init_user_param 

) AS number_generator
CROSS JOIN (SELECT @orderList := 'A,a,B,b,C,c' /* add all to Z,z */) AS init_user_param

) AS letters
INNER JOIN
 Table1
ON
 letters.letter = Table1.name
;

結果

| id  | name |
| --- | ---- |
| 4   | A    |
| 1   | a    |
| 5   | B    |
| 2   | b    |
| 6   | C    |
| 3   | c    |

在數據庫小提琴上查看

請注意，您應該了解一些事情

當您的MySQL使用utf8字符集時， COLLATE utf8mb4_bin可能會改為COLLATE utf8_bin 。

SELECT @orderList := 'A,a,B,b,C,c' /* add all to Z,z */您可能需要添加更多內容到Z,z

Answer 2

這將使新列“ newid”具有您所需的順序

select newid = row_number() over (order by case when val between 'A' and 'Z' 
                                          then  ascii(val) -31 
                                          else ascii(val) end), *

from yourtable

Answer 3

嘗試這樣。 我剛從w3schools使用數據庫，需要檢查MySql是否工作。

SELECT * FROM myTable GROUP BY name ORDER BY UPPER(name), LOWER(name);