mysql數據庫中列轉行

今天突然想到了數據庫中的行專列與列轉行，還不熟悉，在上網看了一下然后就自己寫了個例子。

數據庫表示這樣滴！

//全部查詢出來
SELECT  
(case type  when 'MySql數據庫' then id else NULL END) as  'MySql數據庫',
(case type  when 'SqlServer數據庫' then id  else NULL END) as  'SqlServer數據庫',
(case type  when 'CSharp' then id else NULL END) as  'CSharp',
(case type  when 'Html' then id else NULL END) as  'Html'
from xiaoyao_blogs_essay;

//查詢出他們id的和
SELECT  
sum(case type  when 'MySql數據庫' then id else NULL END) as  'MySql數據庫',
sum(case type  when 'SqlServer數據庫' then id  else NULL END) as  'SqlServer數據庫',
sum(case type  when 'CSharp' then id else NULL END) as  'CSharp',
sum(case type  when 'Html' then id else NULL END) as  'Html'
from xiaoyao_blogs_essay;

//查詢出最大的id
SELECT  
max(case type  when 'MySql數據庫' then id else NULL END) as  'MySql數據庫',
max(case type  when 'SqlServer數據庫' then id  else NULL END) as  'SqlServer數據庫',
max(case type  when 'CSharp' then id else NULL END) as  'CSharp',
max(case type  when 'Html' then id else NULL END) as  'Html'
from xiaoyao_blogs_essay;

//查詢出最小的id
SELECT  
min(case type  when 'MySql數據庫' then id else NULL END) as  'MySql數據庫',
min(case type  when 'SqlServer數據庫' then id  else NULL END) as  'SqlServer數據庫',
min(case type  when 'CSharp' then id else NULL END) as  'CSharp',
min(case type  when 'Html' then id else NULL END) as  'Html'
from xiaoyao_blogs_essay;

//查詢出每列的總數
SELECT  
count(case type  when 'MySql數據庫' then id else NULL END) as  'MySql數據庫',
count(case type  when 'SqlServer數據庫' then id  else NULL END) as  'SqlServer數據庫',
count(case type  when 'CSharp' then id else NULL END) as  'CSharp',
count(case type  when 'Html' then id else NULL END) as  'Html'
from xiaoyao_blogs_essay;

結果