1、filter引用列名时，使用“类名.属性名”的方式，比较使用两个等号“==”

2、filter_by引用列名时，使用“属性名”，比较使用一个等号“=”

3、在使用多条件匹配的时候，filter需要借助sqlalchemy里的and_ ; 而filter_by不需要，直接把多个匹配条件写在一起

4、在使用多条件匹配时，用到>=、>、<=、<的情况，貌似不能使用filter_by。可能是姿势不对

 

filter

(*criterion)

apply the given filtering criterion to a copy of this , using SQL expressions.

e.g.:

session.query(MyClass).filter(MyClass.name == 'some name')

Multiple criteria may be specified as comma separated; the effect is that they will be joined together using the function:

session.query(MyClass).\ filter(MyClass.name == 'some name', MyClass.id > 5)

The criterion is any SQL expression object applicable to the WHERE clause of a select. String expressions are coerced into SQL expression constructs via the construct.

See also

- filter on keyword expressions.

filter_by

(**kwargs)

apply the given filtering criterion to a copy of this , using keyword expressions.

e.g.:

session.query(MyClass).filter_by(name = 'some name')

Multiple criteria may be specified as comma separated; the effect is that they will be joined together using the function:

session.query(MyClass).\ filter_by(name = 'some name', id = 5)

The keyword expressions are extracted from the primary entity of the query, or the last entity that was the target of a call to .

See also

- filter on SQL expressions.