Django_数据库增删改查——查
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查:
filter 支持很多的过滤条件,我们来看下:
contains
包含,相当于sql的like条件
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Entry.objects.get(headline__contains= ‘Lennon‘ ) |
SQL equivalent:
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SELECT ... WHERE headline LIKE ‘%Lennon%‘ ; |
Note this will match the headline ‘Lennon honored today‘ but not ‘lennon honored today‘.
icontains 大小写不敏感
in
In a given iterable; often a list, tuple, or queryset.
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Entry.objects. filter (id__in = [ 1 , 3 , 4 ]) |
SQL equivalent:
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SELECT ... WHERE id IN (1, 3, 4); |
You can also use a queryset to dynamically evaluate the list of values instead of providing a list of literal values:
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inner_qs = Blog.objects. filter (name__contains = ‘Cheddar‘ ) entries = Entry.objects. filter (blog__in = inner_qs) |
This queryset will be evaluated as subselect statement:
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SELECT ... WHERE blog.id IN ( SELECT id FROM ... WHERE NAME LIKE ‘%Cheddar%‘ ) |
gt
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Entry.objects. filter (id__gt = 4 ) |
SQL equivalent:
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SELECT ... WHERE id > 4; |
gte
Greater than or equal to.
lt
Less than.
lte
Less than or equal to.
startswith
Case-sensitive starts-with.
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Entry.objects. filter (headline__startswith = ‘Lennon‘ ) |
SQL equivalent:
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SELECT ... WHERE headline LIKE ‘Lennon%‘ ; |
SQLite doesn’t support case-sensitive LIKE statements; startswith acts like istartswith for SQLite
istartswith
Case-insensitive starts-with.
endswith
Case-sensitive ends-with.
iendswith
Case-insensitive ends-with
range
区间过渡,可对数字、日期进行过滤
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import datetime start_date = datetime.date( 2005 , 1 , 1 ) end_date = datetime.date( 2005 , 3 , 31 ) Entry.objects. filter (pub_date__range = (start_date, end_date)) |
SQL equivalent:
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SELECT ... WHERE pub_date BETWEEN ‘2005-01-01‘ and ‘2005-03-31‘ ; |
Warning!
Filtering a DateTimeField with dates won’t include items on the last day, because the bounds are interpreted as “0am on the given date”. If pub_date was a DateTimeField, the above expression would be turned into this SQL:
SELECT ... WHERE pub_date BETWEEN ‘2005-01-01 00:00:00‘ and ‘2005-03-31 00:00:00‘;
Generally speaking, you can’t mix dates and datetimes.
date
For datetime fields, casts the value as date. Allows chaining additional field lookups. Takes a date value.
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Entry.objects. filter (pub_date__date = datetime.date( 2005 , 1 , 1 )) Entry.objects. filter (pub_date__date__gt = datetime.date( 2005 , 1 , 1 )) |
year
For date and datetime fields, an exact year match. Allows chaining additional field lookups. Takes an integer year.
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Entry.objects. filter (pub_date__year = 2005 ) Entry.objects. filter (pub_date__year__gte = 2005 ) |
SQL equivalent:
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SELECT ... WHERE pub_date BETWEEN ‘2005-01-01‘ AND ‘2005-12-31‘ ; SELECT ... WHERE pub_date >= ‘2005-01-01‘ ; |
When USE_TZ is True, datetime fields are converted to the current time zone before filtering. 简单解决办法是把USE_TZ=False
month
For date and datetime fields, an exact month match. Allows chaining additional field lookups. Takes an integer 1 (January) through 12 (December).
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Entry.objects. filter (pub_date__month = 12 ) Entry.objects. filter (pub_date__month__gte = 6 ) |
When USE_TZ
is True
, datetime fields are converted to the current time zone before filtering. This requires time zone definitions in the database.
SQL equivalent:
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SELECT ... WHERE EXTRACT( ‘month‘ FROM pub_date) = ‘12‘ ; SELECT ... WHERE EXTRACT( ‘month‘ FROM pub_date) >= ‘6‘ ; |
day
For date and datetime fields, an exact day match. Allows chaining additional field lookups. Takes an integer day.
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Entry.objects.filter(pub_date__day=3) Entry.objects.filter(pub_date__day__gte=3) |
SQL equivalent:
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SELECT ... WHERE EXTRACT( ‘day‘ FROM pub_date) = ‘3‘ ; SELECT ... WHERE EXTRACT( ‘day‘ FROM pub_date) >= ‘3‘ ; |
week
For date and datetime fields, return the week number (1-52 or 53) according to ISO-8601, i.e., weeks start on a Monday and the first week contains the year’s first Thursday.
Example:
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Entry.objects. filter (pub_date__week = 52 ) Entry.objects. filter (pub_date__week__gte = 32 , pub_date__week__lte = 38 ) |
week_day
For date and datetime fields, a ‘day of the week’ match. Allows chaining additional field lookups.
Takes an integer value representing the day of week from 1 (Sunday) to 7 (Saturday).
Example:
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Entry.objects.filter(pub_date__week_day=2) Entry.objects.filter(pub_date__week_day__gte=2) |
hour
For datetime and time fields, an exact hour match. Allows chaining additional field lookups. Takes an integer between 0 and 23.
Example:
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Event.objects. filter (timestamp__hour = 23 ) Event.objects. filter (time__hour = 5 ) Event.objects. filter (timestamp__hour__gte = 12 ) |
SQL equivalent:
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SELECT ... WHERE EXTRACT( ‘hour‘ FROM timestamp ) = ‘23‘ ; SELECT ... WHERE EXTRACT( ‘hour‘ FROM time ) = ‘5‘ ; SELECT ... WHERE EXTRACT( ‘hour‘ FROM timestamp ) >= ‘12‘ ;同 |
同时,还支持mintue,second
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Event.objects.filter(time__minute=46) Event.objects.filter(timestamp__second=31) |
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