SQL查询以基于其他列过滤列

Question

I have a relational table that looks something like below:

I want to write a query to which if i give a input of tag_id i need to get the video_id based on the following rule. If the tags belong to the same category then OR condition between tags. If tags belong to different category then AND condition between the tags

tag_id  pvid_id     cat_id  
1       1           1   
1       2           1   
2       2           2

In the above example,

If i give tag_id 1 as the input, the expected output of pvid_id as 1,2

If i give tag_id 1,2 as the input, the expected output of pvid_id is 2

I am unable to fromulate the query, can someone please help me with it or give me a direction towards getting the solution?

Thanks

Answer 1

For one input

Select tag_id, 
group_concat(distinct pvid_id) 
from your_table where tag_id=1 
group by tag_id

For multiple inputs

Select tag_id, 
group_concat(distinct pvid_id) 
from your_table where tag_id 
in('1','2')
group by tag_id

Answer 2

Use group_concat :

select group_concat(pvid_id separator ', ') as result
  from tab
 where tag_id = 1 -- or tag_id = 2

result
 1, 2

SQL Fiddle Demo