Question

我想计算从查询中选择的行数以及所选数据。

SELECT `student`.`student id` AS ID,
    `student unit enrolment`.`session`,
    `student unit enrolment`.`unit code`,
    `units`.`unit name`,
    `workshops`.`campus`,
    `workshops`.`location`,
    CONCAT (
        `teachers`.`first name`,
        " ",
        `teachers`.`last name`
        ) AS Tutor
FROM `student`,
    `student unit enrolment`,
    `units`,
    `workshops`,
    `teachers`
WHERE `student`.`student id` = `student unit enrolment`.`student id`
    AND `student unit enrolment`.`unit code` = `units`.`unit id`
    AND `student unit enrolment`.`unit code` = `workshops`.`unit code`
    AND `workshops`.`teacher id` = `teachers`.`staff id`;

Answer 1

试试这个：

$result = mysql_query(YOUR_QUERY_HERE);
mysql_num_rows($result);

Answer 2

select `student`.`student id` as 'Student ID' , `student unit enrolment`.`session` , `student unit enrolment`.`unit code`
 , `units`.`unit name` , `workshops`.`campus` , `workshops`.`location` , CONCAT(`teachers`.`first name`, " " , `teachers`.`last name`) as Tutor , 

(select count(`student`.`student id`) 
from `student` ,  `student unit enrolment` , `units` , `workshops` , `teachers` 
where `student`.`student id` = `student unit enrolment`.`student id` and `student unit enrolment`.`unit code` =  `units`.`unit id`
and `student unit enrolment`.`unit code` =  `workshops`.`unit code`
and `workshops`.`teacher id` = `teachers`.`staff id`
and `student unit enrolment`.`Year` = '2014') as 'Total count of students'

from `student` ,  `student unit enrolment` , `units` , `workshops` , `teachers`
where `student`.`student id` = `student unit enrolment`.`student id`
and `student unit enrolment`.`unit code` =  `units`.`unit id`
and `student unit enrolment`.`unit code` =  `workshops`.`unit code`
and `workshops`.`teacher id` = `teachers`.`staff id`
and  `student unit enrolment`.`Year` = '2014'

Order by `student unit enrolment`.`session` , `student unit enrolment`.`unit code` , `workshops`.`location` , `workshops`.`class times`

如何计算SQL中的选定行

2 个答案: