Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
334 views
in Technique[技术] by (71.8m points)

sql - MYSQL - Concatenate two tables

I have two tables as follows:

    TABLE A                    TABLE B
 StuID | actid              FacID | actid
  3       12                  98      17
  5       17                  54      21

I want to list the name of everyone, both students and faculty, who participate in activity 17. Is there anyway I can get a result as below:

 id  | actid
 98     17
 5      17

WITHOUT creating a new table (by just using nesting of expressions or derived relations) ?

A JOIN on the actid would give something like:

StuID  | FacID  | actid
 5        98        17

I guess I need a form of concatenation??

See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Reply

0 votes
by (71.8m points)
select * from table_a where actid = 17
union all
select * from table_b where actid = 17

You may (or may not) need to do something about the ids not being unique, such as

select 'Student', table_a.* from table_a where actid = 17
union all
select 'Faculty', table_b.* from table_b where actid = 17

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
OGeek|极客中国-欢迎来到极客的世界,一个免费开放的程序员编程交流平台!开放,进步,分享!让技术改变生活,让极客改变未来! Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...