mysql选择动态行作为列名
我正在尝试以这种格式创建一个表。我如何才能做到这一点mysql选择动态行作为列名,mysql,rows,dynamic-columns,Mysql,Rows,Dynamic Columns,我正在尝试以这种格式创建一个表。我如何才能做到这一点 Student_id | Skill_id | skill-Score 1 30 5 1 50 1 1 63 2 1 42 2 2 30 7 2 50 3
Student_id | Skill_id | skill-Score
1 30 5
1 50 1
1 63 2
1 42 2
2 30 7
2 50 3
2 63 6
2 42 9
Student_id || 30 || 50 || 63 || 42 |
1 5 1 2 2
2 7 3 6 9
如果技能ID的数量已知且固定，则可以使用简单的透视查询：
SELECT CONCAT(
'SELECT `r_job_scores`.id_score', GROUP_CONCAT('
, `t_', REPLACE(skill_id, '`', '``'), '`.value
AS `', REPLACE(skill_id, '`', '``'), '`'
SEPARATOR ''),
' FROM `r_job_scores` ', GROUP_CONCAT('
LEFT JOIN `r_job_scores` AS `t_', REPLACE(skill_id, '`', '``'), '`
ON `r_job_scores`.id_score = `t_', REPLACE(skill_id, '`', '``'), '`.id_score
AND `t_', REPLACE(skill_id, '`', '``'), '`.skill_id = ', QUOTE(skill_id)
SEPARATOR ''),
' GROUP BY `r_job_scores`.id_score'
)
SELECT Student_Id,
MAX(CASE WHEN Skill_id = 30 THEN skill-Score END) AS `30`,
MAX(CASE WHEN Skill_id = 50 THEN skill-Score END) AS `50`,
MAX(CASE WHEN Skill_id = 63 THEN skill-Score END) AS `63`,
MAX(CASE WHEN Skill_id = 42 THEN skill-Score END) AS `42`
FROM r_job_scores
GROUP BY Student_Id
如果技能ID的数量已知且固定，则可以使用简单的透视查询：
SELECT CONCAT(
'SELECT `r_job_scores`.id_score', GROUP_CONCAT('
, `t_', REPLACE(skill_id, '`', '``'), '`.value
AS `', REPLACE(skill_id, '`', '``'), '`'
SEPARATOR ''),
' FROM `r_job_scores` ', GROUP_CONCAT('
LEFT JOIN `r_job_scores` AS `t_', REPLACE(skill_id, '`', '``'), '`
ON `r_job_scores`.id_score = `t_', REPLACE(skill_id, '`', '``'), '`.id_score
AND `t_', REPLACE(skill_id, '`', '``'), '`.skill_id = ', QUOTE(skill_id)
SEPARATOR ''),
' GROUP BY `r_job_scores`.id_score'
)
SELECT Student_Id,
MAX(CASE WHEN Skill_id = 30 THEN skill-Score END) AS `30`,
MAX(CASE WHEN Skill_id = 50 THEN skill-Score END) AS `50`,
MAX(CASE WHEN Skill_id = 63 THEN skill-Score END) AS `63`,
MAX(CASE WHEN Skill_id = 42 THEN skill-Score END) AS `42`
FROM r_job_scores
GROUP BY Student_Id
您可以使用动态sql实现这一点 查询
SELECT t.Student_Id,
t.`30` + t.`50` + t.`63` + t.`42` AS overall_score
FROM
(
SELECT Student_Id,
MAX(CASE WHEN Skill_id = 30 THEN skill-Score END) AS `30`,
MAX(CASE WHEN Skill_id = 50 THEN skill-Score END) AS `50`,
MAX(CASE WHEN Skill_id = 63 THEN skill-Score END) AS `63`,
MAX(CASE WHEN Skill_id = 42 THEN skill-Score END) AS `42`
FROM r_job_scores
GROUP BY Student_Id
) t
set @query = null;
select
group_concat(distinct
concat(
'max(case when `Skill_id` = ',
`Skill_id`, ' then `skill-Score` end) as `', `Skill_id` , '`'
)
) into @query
from `your_table_name`;
set @query = concat('select `Student_id`, ', @query, ' from `your_table_name`
group by `Student_id`
');
prepare stmt from @query;
execute stmt;
deallocate prepare stmt;
您可以使用动态sql实现这一点 查询
SELECT t.Student_Id,
t.`30` + t.`50` + t.`63` + t.`42` AS overall_score
FROM
(
SELECT Student_Id,
MAX(CASE WHEN Skill_id = 30 THEN skill-Score END) AS `30`,
MAX(CASE WHEN Skill_id = 50 THEN skill-Score END) AS `50`,
MAX(CASE WHEN Skill_id = 63 THEN skill-Score END) AS `63`,
MAX(CASE WHEN Skill_id = 42 THEN skill-Score END) AS `42`
FROM r_job_scores
GROUP BY Student_Id
) t
set @query = null;
select
group_concat(distinct
concat(
'max(case when `Skill_id` = ',
`Skill_id`, ' then `skill-Score` end) as `', `Skill_id` , '`'
)
) into @query
from `your_table_name`;
set @query = concat('select `Student_id`, ', @query, ' from `your_table_name`
group by `Student_id`
');
prepare stmt from @query;
execute stmt;
deallocate prepare stmt;
如果您需要php/html格式的输出（它以前被标记为php…），您只需要
按学生id、技能id从r_作业中选择*即可根据需要构建表。如果您需要php/html格式的输出（它以前被标记为php…），您只需要按学生id从r_作业中选择*即可，Skill_id
能够根据需要构建表格。谢谢。。我有一个疑问，我想把学生技能的总和作为学生1（5+1+2+2）的总分。我该怎么做呢？谢谢。。我有一个疑问，我想把学生技能的总和作为整体分数来计算。Skill\u idSkill\u id