Question

我想获得存储在字段myfield（varchar（128））中的所有字符串大小及其出现次数（即具有该特定长度的行数）。这就是我到目前为止所做的：

MySQL > SELECT SUM(CHAR_LENGTH(myfield)=5) as occurr from mytable;
+--------+
| occurr |
+--------+
|   9194 |
+--------+
1 row in set (0.39 sec) 

MySQL > SELECT SUM(CHAR_LENGTH(myfield)=6) as occurr from mytable;
+--------+
| occurr |
+--------+
|  11636 |
+--------+
1 row in set (0.44 sec)  

MySQL > SELECT SUM(CHAR_LENGTH(myfield)=7) as occurr from mytable;
+--------+
| occurr |
+--------+
|  19022 |
+--------+
1 row in set (0.48 sec)

有没有办法用一个SQL命令获取这些数据？像这样的输出：

+--------+--------+
| length | occurr |
+--------+--------+
|      5 |   9194 |
+--------+--------+
|      6 |  11636 |
+--------+--------+
|      7 |  19022 |
+--------+--------+

Answer 1

您可以简单地使用：

SELECT CHAR_LENGTH(myfield) AS length, COUNT(*) AS occurr
FROM mytable
WHERE CHAR_LENGTH(myfield) IN (5,6,7)
GROUP BY CHAR_LENGTH(myfield)

如果您对某些特定字符长度不感兴趣，您当然可以删除WHERE子句。

Answer 2

SELECT CHAR_LENGTH(my_field) AS长度为, COUNT(*) AS {occurr {1}} {mytable的{1}}

我还在打字，因为另一个答案出现了。基本相同 - 除了包含CHAR_LENGTH（）没有限制。

Answer 3

SELECT CHAR_LENGTH(myfield) as length, COUNT(*) as occurence FROM mytable WHERE CHAR_LENGTH(myfield) BETWEEN 4 and 6 GROUP BY length

编辑：我或多或少地同时发布了相同的答案。我当然不打算偷一个答案。

MySQL - 获取存储在字段中的所有字符串大小

3 个答案: