從表列中統計 0 和 1 的數量並將其顯示在兩列中的 MySQL 查詢是什麼?
為此,您可以使用聚合函式 SUM()。我們首先建立一個表 −
mysql> create table DemoTable ( isMarried tinyint(1) ); Query OK, 0 rows affected (0.84 sec)
使用 insert 命令向表中插入一些記錄 −
mysql> insert into DemoTable values(0); Query OK, 1 row affected (0.26 sec) mysql> insert into DemoTable values(1); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable values(1); Query OK, 1 row affected (0.21 sec) mysql> insert into DemoTable values(0); Query OK, 1 row affected (0.20 sec) mysql> insert into DemoTable values(1); Query OK, 1 row affected (0.19 sec) mysql> insert into DemoTable values(1); Query OK, 1 row affected (0.20 sec) mysql> insert into DemoTable values(0); Query OK, 1 row affected (0.12 sec)
使用 select 語句顯示錶中的所有記錄 −
mysql> select *from DemoTable;
這將產生以下輸出 −
+-----------+ | isMarried | +-----------+ | 0 | | 1 | | 1 | | 0 | | 1 | | 1 | | 0 | +-----------+ 7 rows in set (0.00 sec)
以下是統計一列中的 0 和 1 的數量並將其顯示在兩列中的查詢 −
mysql> select sum(tbl.isMarried=1) as all_one_count, sum(tbl.isMarried=0) as all_zero_count, sum(tbl.isMarried in(0,1)) as all_zero_count_and_one_count from DemoTable tbl;
這將產生以下輸出 −
+---------------+----------------+------------------------------+ | all_one_count | all_zero_count | all_zero_count_and_one_count | +---------------+----------------+------------------------------+ | 4 | 3 | 7 | +---------------+----------------+------------------------------+ 1 row in set (0.04 sec)
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