12/30/2023 0 Comments Mysql count distinct group by![]() ![]() (sql, params), where sql is the SQL string, and params is ![]() Generates the SQL fragment for the database function. as_sql( compiler, connection, function = None, template = None, arg_joiner = None, ** extra_context) ¶ If this attribute is set and the function is called with aĭifferent number of expressions, TypeError will be raised. arity ¶Ī class attribute that denotes the number of arguments the functionĪccepts. arg_joiner ¶Ī class attribute that denotes the character used to join the list ofĮxpressions together. Interpolation with the query parameters in the database cursor. Template attribute because the string is interpolated twice: onceĭuring the template interpolation in as_sql() and once in the SQL Literal % character in the query, quadruple it ( %%%%) in the If you’re constructing SQL like strftime('%W', 'date') and need a ![]() template ¶Ī class attribute, as a format string, that describes the SQL that is Specifically, the function will be interpolated as the function The Func API is as follows: class Func( * expressions, ** extra) ¶ function ¶Ī class attribute describing the function that will be generated. See Database Functions for a list of built-in database functions. ( need_chairs=GreaterThan(F('num_employees'), F('num_chairs')), ) from django.db.models import Exists ( Exists((company=OuterRef('pk'), salary_gt=10)) ) # Lookup expressions can also be used directly in filters (GreaterThan(F('num_employees'), F('num_chairs'))) # or annotations. from django.db.models import CharField from django.db.models.functions import Length CharField.register_lookup(Length) _by('name_length') # Boolean expression can be used directly in filters. (num_products=Count('products')) (num_products=Count(F('products'))) # Aggregates can contain complex computations also (num_offerings=Count(F('products') + F('services'))) # Expressions can also be used in order_by(), either directly _by(Length('name').asc()) _by(Length('name').desc()) # or using the double underscore lookup syntax. ticker 'GOOG' # Annotate models with an aggregated value. create ( name = "Google", ticker = Upper ( Value ( "goog" ))) # Be sure to refresh it if you need to access the field. chairs_needed 70 # Create a new company using expressions. annotate ( chairs_needed = F ( "num_employees" ) - F ( "num_chairs" )). filter ( num_employees_gt = F ( "num_chairs" )). filter ( num_employees_gt = F ( "num_chairs" ) + F ( "num_chairs" )) # How many chairs are needed for each company to seat all employees? > company = (. filter ( num_employees_gt = F ( "num_chairs" ) * 2 ) > Company. filter ( num_employees_gt = F ( "num_chairs" )) # Find companies that have at least twice as many employees # as chairs. If you run two upper queries you have: `2`īecause exist two different account_id (10 and 12) and only in the last year (2010) account_ids 10 and 12 have written their rows.> from django.db.models import Count, F, Value > from django.db.models.functions import Length, Upper > from django.db.models.lookups import GreaterThan # Find companies that have more employees than chairs. I suppose this data set of order couple: (year, account_id) `2008 10` select CalendarYear,count(distinct account_id) as accountCount Grouped by CalendarYear so if you have an account_id in two different years, this information goes in two different rows. Return a count of different accounts (over all years), so if you have an account_id present in two years, you have 1 (count) returned. The first: select count(distinct account_id) Select d.CalendarYear, count (distinct EmployeeKey) as Employecount I did not quite understand reason/answer given to my question in the 2 replies so I would like to add 2 queries below using AdventureWorksDW2008R2 where no count is missing: select count (distinct EmployeeKey) To debug I run following query if I have missing date_id in FactCustomerAccount but found no missing keys: select distinct f.date_id from FactCustomerAccount fĬan anyone please suggest what could be the reason for missing 12 counts? I am not sure why I am missing 12 counts. The query and output is below: select CalendarYear,count(distinct account_id) as accountCount My question is if I use the query below I get correct count which is 90: select count(distinct account_id)īut when I group by CalendarYear as below I am missing 12 counts. I have already searched SO but found no answer to my question. ![]()
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