Mysql Sql语句将行切成两半
这是我当前的sql查询Mysql Sql语句将行切成两半,mysql,select,into-outfile,Mysql,Select,Into Outfile,这是我当前的sql查询 SELECT w.city, t.tmc, t.date, t.time, w.event, ROUND(AVG(w.Pave), 0) surface_temperature, ROUND(AVG(w.Air), 0) air_temperature, ROUND(AVG(a.material_rate),0) material_rate, w.intensity, t.avg FROM win
SELECT
w.city, t.tmc, t.date, t.time, w.event,
ROUND(AVG(w.Pave), 0) surface_temperature,
ROUND(AVG(w.Air), 0) air_temperature,
ROUND(AVG(a.material_rate),0) material_rate,
w.intensity, t.avg
FROM winter2010.traffictest t
LEFT OUTER JOIN winter2010.application a ON a.DATE = t.DATE AND a.tmc = t.tmc AND a.tmc = t.tmc AND Left(a.time,2) = Left(t.time, 2)
LEFT OUTER JOIN winter2010.weather w ON t.DATE = w.DATE AND t.tmc = w.tmc AND Left(t.time, 2) = Left(w.time, 2)
GROUP BY tmc, t.time
INTO OUTFILE 'c:/sass2.csv' FIELDS TERMINATED BY ',' OPTIONALLY ENCLOSED BY '"' LINES
TERMINATED BY '\n';
我从下面的sql语句创建这个csv文件,它工作得很好,除了一件事,它只占用1/2行
traffictest中总共有2661行
当我将数据输出到csv时,它只输入1331
我改变了traffictest的大小,这是正确的,除了当我只有3排时,它实际上拉了所有3排
如果您能帮助您解决这个问题,我们将不胜感激。当您使用
groupby
MySql时,每个组只返回一行,您的行具有相似的tmc时间,而MySql只为所有这些行返回一行,这就是行数减少的原因。我猜问题出在groupby tmc,t.time
;太多行被分组在一起。如果你把小组放在旁边,你会得到多少行?也许您应该将此子句替换为group by t.primary\u key\u of t