mysql-如何结合三个表在mysql中查找Avg，High，Low值？

Question

我有三个不同的表，例如

  prac_test
UID | net_wpm
5        58
5        67

 multi_test
UID | net_wpm
5        88
5        97

 shadow_test
UID | net_wpm
5        8
5        77

如何组合这三个表并获得UID 5的平均值，高，低净wpm

预先感谢

Answer 1

这应该有效，请摆弄它：) http://www.sqlfiddle.com/#!9/fa438b/16

因此我将所有表合并在一起，并从MAX中选择了MIN，AVG和net_wpm

     SELECT AVG(net_wpm),Max(net_wpm),MIN(net_wpm)
  FROM  (
select UID,net_wpm from prac_test 
union all
select UID,net_wpm from multi_test 
union all
select UID,net_wpm from shadow_test  ) sub