是否有一种方法可以在执行查询时显示Django正在运行的SQL ?


当前回答

下面基于https://code.djangoproject.com/ticket/17741:返回有效的SQL查询

def str_query(qs):
    """
    qs.query returns something that isn't valid SQL, this returns the actual
    valid SQL that's executed: https://code.djangoproject.com/ticket/17741
    """
    cursor = connections[qs.db].cursor()
    query, params = qs.query.sql_with_params()
    cursor.execute('EXPLAIN ' + query, params)
    res = str(cursor.db.ops.last_executed_query(cursor, query, params))
    assert res.startswith('EXPLAIN ')
    return res[len('EXPLAIN '):]

其他回答

虽然可以使用提供的代码来完成,但我发现使用调试工具栏应用程序是显示查询的一个很好的工具。你可以从github下载。

这使您可以选择显示在给定页面上运行的所有查询以及查询所花费的时间。它还汇总了页面上的查询数量以及用于快速查看的总时间。当你想了解Django ORM在幕后做了什么时,这是一个很好的工具。它也有很多其他不错的功能,你可以使用,如果你喜欢。

如果您需要为一些自定义SQL重用查询,还有另一种非常有用的方法。我曾在一个分析应用程序中使用过这种方法,它远远超出了Django的ORM所能轻松完成的范围,所以我将ORM生成的SQL作为子查询包含进来。

from django.db import connection
from myapp.models import SomeModel

queryset = SomeModel.objects.filter(foo='bar')

sql_query, params = queryset.query.as_sql(None, connection)

这将为您提供带有占位符的SQL,以及可以使用的带有查询参数的元组。你可以直接把它传递给DB:

with connection.connection.cursor(cursor_factory=DictCursor) as cursor:
    cursor.execute(sql_query, params)
    data = cursor.fetchall()

我已经做了一个你可以使用的小片段:

from django.conf import settings
from django.db import connection


def sql_echo(method, *args, **kwargs):
    settings.DEBUG = True
    result = method(*args, **kwargs)
    for query in connection.queries:
        print(query)
    return result


# HOW TO USE EXAMPLE:
# 
# result = sql_echo(my_method, 'whatever', show=True)

它以参数函数(包含sql查询)来检查和args, kwargs需要调用该函数。结果它返回函数返回的内容,并在控制台中打印SQL查询。

我为此开发了一个扩展,所以你可以很容易地在你的视图函数上放一个装饰器,看看有多少查询被执行了。

如何安装:

$ pip install django-print-sql

用作上下文管理器:

from django_print_sql import print_sql

# set `count_only` to `True` will print the number of executed SQL statements only
with print_sql(count_only=False):

  # write the code you want to analyze in here,
  # e.g. some complex foreign key lookup,
  # or analyzing a DRF serializer's performance

  for user in User.objects.all()[:10]:
      user.groups.first()

装饰:用作装饰:

from django_print_sql import print_sql_decorator


@print_sql_decorator(count_only=False)  # this works on class-based views as well
def get(request):
    # your view code here

Github: https://github.com/rabbit-aaron/django-print-sql

从django获取查询结果到数据库(使用正确的参数替换) 你可以使用这个函数:

from django.db import connection

def print_database_query_formatted(query):
    sql, params = query.sql_with_params()
    cursor = connection.cursor()
    cursor.execute('EXPLAIN ' + sql, params)
    db_query = cursor.db.ops.last_executed_query(cursor, sql, params).replace('EXPLAIN ', '')

    parts = '{}'.format(db_query).split('FROM')
    print(parts[0])
    if len(parts) > 1:
        parts = parts[1].split('WHERE')
        print('FROM{}'.format(parts[0]))
        if len(parts) > 1:
            parts = parts[1].split('ORDER BY')
            print('WHERE{}'.format(parts[0]))
            if len(parts) > 1:
                print('ORDER BY{}'.format(parts[1]))

# USAGE
users = User.objects.filter(email='admin@admin.com').order_by('-id')
print_database_query_formatted(users.query)

输出示例

SELECT "users_user"."password", "users_user"."last_login", "users_user"."is_superuser", "users_user"."deleted", "users_user"."id", "users_user"."phone", "users_user"."username", "users_user"."userlastname", "users_user"."email", "users_user"."is_staff", "users_user"."is_active", "users_user"."date_joined", "users_user"."latitude", "users_user"."longitude", "users_user"."point"::bytea, "users_user"."default_search_radius", "users_user"."notifications", "users_user"."admin_theme", "users_user"."address", "users_user"."is_notify_when_buildings_in_radius", "users_user"."active_campaign_id", "users_user"."is_unsubscribed", "users_user"."sf_contact_id", "users_user"."is_agree_terms_of_service", "users_user"."is_facebook_signup", "users_user"."type_signup" 
FROM "users_user" 
WHERE "users_user"."email" = 'admin@admin.com' 
ORDER BY "users_user"."id" DESC

它基于这个票证评论:https://code.djangoproject.com/ticket/17741#comment:4