让我们首先来看一个创建表,添加记录并显示它们的示例。CREATE命令用于创建表。
mysql> CREATE table RowCountDemo -> ( -> ID int, -> Name varchar(100) > );
使用INSERT命令插入记录。
mysql>INSERT into RowCountDemo values(1,'Larry'); mysql>INSERT into RowCountDemo values(2,'John'); mysql>INSERT into RowCountDemo values(3,'Bela'); mysql>INSERT into RowCountDemo values(4,'Jack'); mysql>INSERT into RowCountDemo values(5,'Eric'); mysql>INSERT into RowCountDemo values(6,'Rami'); mysql>INSERT into RowCountDemo values(7,'Sam'); mysql>INSERT into RowCountDemo values(8,'Maike'); mysql>INSERT into RowCountDemo values(9,'Rocio'); mysql>INSERT into RowCountDemo values(10,'Gavin');
显示记录。
mysql>SELECT *from RowCountDemo;
以下是上述查询的输出。
+------+-------+ | ID | Name | +------+-------+ | 1 | Larry | | 2 | John | | 3 | Bela | | 4 | Jack | | 5 | Eric | | 6 | Rami | | 7 | Sam | | 8 | Maike | | 9 | Rocio | | 10 | Gavin | +------+-------+ 10 rows in set (0.00 sec)
为了快速计算行数,我们有以下两个选项-
mysql >SELECT count(*) from RowCountDemo;
以下是上述查询的输出。
+----------+ | count(*) | +----------+ | 10 | +----------+ 1 row in set (0.00 sec)
mysql>SELECT count(found_rows()) from RowCountDemo;
以下是上述查询的输出。
+---------------------+ | count(found_rows()) | +---------------------+ | 10 | +---------------------+ 1 row in set (0.00 sec)