sql group by語法與實例
group by 語句
group by 語句用於結合合計函數，根據一個或多個列對結果集進行分組。
sql group by 語法
select column_name, aggregate_function(column_name)
from table_name
where column_name operator value
group by column_name
來看一個group by實例
比如表裡內容是這樣
gameid best top spam
111 1 1 1
121 1 1 0
123 0 1 1
111 1 0 1
我現在要取出best top spam 的數量 結果應該是
gameid best top spam
111 2 1 2
121 1 1 0
123 0 1 1
select gameid, sum(best) as bestcnt, sum(top) as tocnt, sum(spam) as spamcnt
from table
group by gameid
在php教程 中使用方法
$sql = "select gameid,sum(best) as best,sum(top) as top,sum(spam) as spam, from tablename group by gameid order by gameid asc";
再來看個簡單一點的實例
數據庫教程表table
日期 勝負
2009-12-9 勝
2009-12-9 勝
2009-12-9 負
2009-12-9 負
2009-12-10 負
2009-12-10 勝
2009-12-10 負
查詢結果
日期 勝 負
2009-12-9 2 2
2009-12-10 1 2
select 日期,
sum(decode(勝負,'勝',1,0)),
sum(decode(勝負,'負',1,0))
from 數據庫表
group by 日期
