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法律研究如何計算 MySQL 中某一列中最常出現的 10 個值？
要統計 MySQL 表中某一列中最常出現的 10 個值，語法如下 -
SELECT yourColumnName, count(*) FROM yourTableName GROUP BY yourColumnName ORDER BY count(*) DESC LIMIT 10;
為理解上述語法，讓我們建立一個表。建立表的查詢如下 -
mysql> create table countTop10Demo -> ( -> Value int -> ); Query OK, 0 rows affected (0.74 sec)
使用 insert 命令在表中插入一些記錄。查詢如下 -
mysql> insert into countTop10Demo values(10); Query OK, 1 row affected (0.12 sec) mysql> insert into countTop10Demo values(1100); Query OK, 1 row affected (0.11 sec) mysql> insert into countTop10Demo values(200); Query OK, 1 row affected (0.11 sec) mysql> insert into countTop10Demo values(2100); Query OK, 1 row affected (0.10 sec) mysql> insert into countTop10Demo values(1100); Query OK, 1 row affected (0.11 sec) mysql> insert into countTop10Demo values(450); Query OK, 1 row affected (0.28 sec) mysql> insert into countTop10Demo values(600); Query OK, 1 row affected (0.12 sec) mysql> insert into countTop10Demo values(2100); Query OK, 1 row affected (0.16 sec) mysql> insert into countTop10Demo values(150); Query OK, 1 row affected (0.16 sec) mysql> insert into countTop10Demo values(16454); Query OK, 1 row affected (0.10 sec) mysql> insert into countTop10Demo values(450); Query OK, 1 row affected (0.12 sec) mysql> insert into countTop10Demo values(2350); Query OK, 1 row affected (0.10 sec) mysql> insert into countTop10Demo values(1780); Query OK, 1 row affected (0.15 sec) mysql> insert into countTop10Demo values(1345); Query OK, 1 row affected (0.22 sec) mysql> insert into countTop10Demo values(34); Query OK, 1 row affected (0.15 sec) mysql> insert into countTop10Demo values(2100); Query OK, 1 row affected (0.08 sec) mysql> insert into countTop10Demo values(19034); Query OK, 1 row affected (0.12 sec) mysql> insert into countTop10Demo values(1844); Query OK, 1 row affected (0.11 sec) mysql> insert into countTop10Demo values(34); Query OK, 1 row affected (0.08 sec) mysql> insert into countTop10Demo values(16454); Query OK, 1 row affected (0.19 sec)
現在你可以使用 select 語句顯示錶中的所有記錄。查詢如下 -
mysql> select *from countTop10Demo;
輸出如下 -
+-------+ | Value | +-------+ | 10 | | 1100 | | 200 | | 2100 | | 1100 | | 450 | | 600 | | 2100 | | 150 | | 16454 | | 450 | | 2350 | | 1780 | | 1345 | | 34 | | 2100 | | 19034 | | 1844 | | 34 | | 16454 | +-------+ 20 rows in set (0.00 sec)
以下查詢用於選擇 MySQL 中某一列中最常出現的 10 個值 -
mysql> SELECT Value, count(*) -> FROM countTop10Demo -> GROUP BY Value -> ORDER BY count(*) DESC -> LIMIT 10;
輸出如下 -
+-------+----------+ | Value | count(*) | +-------+----------+ | 2100 | 3 | | 1100 | 2 | | 34 | 2 | | 450 | 2 | | 16454 | 2 | | 1780 | 1 | | 200 | 1 | | 1345 | 1 | | 19034 | 1 | | 600 | 1 | +-------+----------+ 10 rows in set (0.00 sec)
更新時間：2019-07-30
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