MySQL - 用condintion删除一行

时间:2017-06-08 17:52:55

标签: mysql conditional-statements sql-delete

我有一个动物园数据库,当一个容器里面没有动物时我必须删除一行。我试过这个:

curl --data "field=value" http://127.0.0.1:8081/

我收到了这个错误:

DELETE FROM container
WHERE (SELECT COUNT(NameAnimal), NameContainer 
FROM animal, container
WHERE container.CodContainer =
animal.CodContainer AND
animal.CodContainer =
container.CodContainer
GROUP BY container.CodContainer) = 0;`

有什么想法吗?

2 个答案:

答案 0 :(得分:0)

你的问题是你的where子句。你得到NameAnimal和NameContainer的计数,并检查它们是否等于0.这不能工作,因为你采取两列,然后看看它们是否等于一个0.我假设你可能想要删除部分使用NameContainer的select语句来解决您的问题。

答案 1 :(得分:0)

我使用names =["timestamp","heure","lat","lon","impact","type"] data = pd.read_csv('flash.txt',names=names, parse_dates=['timestamp'],index_col=['timestamp'], dayfirst=True) spring = range(80, 172) summer = range(172, 264) fall = range(264, 355) def season(x): if x in spring: return 'Spring' if x in summer: return 'Summer' if x in fall: return 'Fall' else : return 'Winter' data['SEASON'] = data.index.to_series().dt.month.map(lambda x : season(x)) data['impact'] = data['impact'].abs() seasonly = data.groupby('SEASON')['impact'].mean() 和一个小选择

来完成
NOT IN