mongodb aggregate functions

You need to add translatefields values to the following collection according to Lastupdate by day.Rs_test:secondary>db.new_result.find ();{ "_id" :objectid (" 57fb0756e31f84a56ed41889 ")," Lastupdate ":isodate (" 2016-09-02t01:35:02.471z ")," Translatefields ":9}{" _id ":objectid (" 57fb0756e31f84a56ed4188a ")," Lastupdate ":isodate (" 2016-09-05t11:13:28.344z ")," Translatefields ":10}{" _id ":objectid (" 57fb0756e31f84a56ed4188b ")," Lastupdate ":isodate (" 2016-09-05t09:26:41.016z ")," Transl

Aggregate functions in the statistics of a ~, are often common gray. But there's a little bit to be aware of.Create Table#Tmp (AintBint )Insert into#Tmp (A, B)Values(1,NULL),(NULL,NULL),(NULL,3),(2,4)Select * from#Tmpa b----------- -----------1 NULLNULL NULLNULL 32 4Here I'll simply try using the count and Sum and AVG 3 most commonly used

MySQL Aggregate functions I. AVG AVG (col) Returns the average value of a specified column. Ii. COUNT COUNT (col) Returns the number of non-NULL values in the specified column. 3. MIN/MAX MIN (col): returns the minimum value of a specified column. MAX (col): returns the maximum value of a specified column. Iv. SUM SUM (col) Returns the sum of all values of a specified column. 5. GROUP_CONCAT GROUP_CONCAT ([

Aggregate functions count, max, min, avg, sum...Select count (*) from T_EmployeeSelect Max (FSalary) from T_EmployeeSort ASC ascending DESC descendingSelect * from T_Employee order by FageSort by age in descending order. Sort by salary in ascending order if the age is the sameSelect * from T_Employee order by FAge DESC, FSalary ASCOrder by must be placed after the where clauseWildcard FilterUse like for wil

~ present: UF software 2 1995-01-01~2003-06-29: Microsoft China, 2004-07-01~2009-06-29: Shanda Network The SqlStrConcate.dll code (online Help from SQL Server) is as follows: Using System; Using System.Data; Using Microsoft.SqlServer.Server; Using System.Data.SqlTypes; Using System.IO; Using System.Text;[Serializable] [Sqluserdefinedaggregate (Format.userdefined,//use CLR serialization to serialize the intermediate result Isinvar Ianttonulls = True,//optimizer property Isinvarianttoduplicate

After one weeks, I finally began to write a third article. Get Up!Aggregation functions:The aggregate functions provided in SQL can be used to count, sum, find the most value, and so on.Classification:–count: Number of statistics rows–sum: Gets the aggregate value of a single column–avg: Calculating the average of a column– Max: Calculating the maximum value of a

Learn MySQL with teacher Wang: aggregate functionsTeacher: Wang Shaohua QQ Group No.: 483773664 Learning Content Usage of COUNT (), SUM (), AVG (), MAX (), and Min () four aggregate functionsThe aggregate functions include count (), SUM (), AVG (), MAX (), and Min ().One, COUNT ()(a) IntroductionThe count () function

Aggregate functions count, max, min, avg, sum... Select count (*) from T_Employee Select Max (FSalary) from T_Employee Sort ASC ascending DESC descendingSelect * from T_Employee order by Fage Sort by age in descending order. Sort by salary in ascending order if the age is the sameSelect * from T_Employee order by FAge DESC, FSalary ASC Order by must be placed after the where clause Wildcard FilterUse like

Listagg (column name, ' Split symbol ') Oracle 11g above a multiple-row query result with the specified column name merged into one line with the specified split symbol: For example: Table raw DATA: Requirements: The data in the Mb1_transport_license_list table is grouped according to the transportation_license_id data, and the data of the Item_category_name column is merged. Using aggregate functions Lis

Label:We all know that when a case is applied in SQL, the information in the database is converted For example, select (Case sex if 0 then ' men ' else ' end) as sex from Studentinfo So what does it do in the aggregate function? SELECTSex fromStudentSELECTSexCOUNT(*) asNum fromStudentGROUP bySexSELECTSex,province,COUNT(*) asNum fromStudentGROUP bysex,provinceSELECTSex,province,COUNT(province) asNum fromStudentGROUP bysex,provinceSELECTSex,provin

Tags: style blog http color ar using SP strong dataUsually because of the database study is not deep, so in the interview asked some of the usual encountered problems incredibly can not be very sure to answer, really let oneself very angry!One of the things that impressed me this time is:when using aggregate functions in MySQL such as AVG (t), T is a field of type int in the table, nullable, with three rows

Aggregation function: A function that summarizes multirow (row) data into a row according to certain rules, and before summarizing the data, you can group the data by a specific column (Coloumn) and then filter by the criteria given again.A: Count function1 SELECT COUNT (Birthday) from customer2 SELECT COUNT (*) from customer3 SELECT COUNT (1) from customer1 and 2 differences: Using a specific column name as a parameter, the column does not calculate the null value of the column within countBoth

([Partition_by_clause] order_by_clause) Example:SELECT MIN ([UnitsInStock]) from [dbo]. [Product]SELECT [Categoryid],min ([UnitsInStock]) from [dbo].[ Product]group by [CategoryID]6. COUNTReturns the number of items in a group. COUNT is similar to the COUNT_BIG function. The only difference between the two functions is their return value. COUNT always returns the int data type value. Count_big always returns the bigint data type value.Grammar:COUN

Tags: An aggregate function is a function that performs a calculation on a set of values and returns a single value, which is often used in conjunction with the GROUP BY clause of a SELECT statement, and what aggregate functions are specifically in SQL SERVER? Let's take a look at: 1. AVG returns the average in the specified group, and the null value is ignored.

See the following table: aggregationtable ID Name 1 Zhao 2 Money 1 Sun 1 Li 2 Week If you want to obtain the aggregation result ID Name 1 Zhao Sun Li 2 Qian Zhou Sum, AVG, Count, count (*), Max, and Min cannot be used. These are the aggregation of values. However, we can solve this problem through user-defined

The aggregate functions are shown in the following table: Function Parameters Function COUNT ([all| Distinct]expression) Calculates the number of non-null values in an expression, which can be used for numeric columns, and to remove duplicate values when using Distice COUNT (*) Calculates all rows, including null rows, and cannot use the DISTINCT

Label:SELECT AA. [User_id],cc.[user_name],dd. Name as DEPNAME,AA. Module_id,aa. Module_name,SUM (case AA. Operate_type when ' 2 ' and then Operatenum END ' as ' addnum ',SUM (case AA. Operate_type when ' 3 ' and then Operatenum END ' as ' editnum ',SUM (case AA. Operate_type when ' 4 ' then operatenum END) as ' Delnum 'From (SELECT A.[user_id],a.module_id,c.module_name,a.operate_type,count (1) as Operatenum from dbo. Sys_user_log as aINNER JOIN dbo. Sys_module as C on a.module_id = c.module_idWH

-01-01t00:00:00z) unless you specify a lower bound time range. Then they go back to the time stamp of the Nether.The same set of execution sum () at the float64 point may produce slightly different results. Influxdb before the function is not applicable, results in those small difference sorting points. Example 2 The calculations are grouped in 5 days, Water_level and SELECT SUM(water_level) FROM h2o_feet WHERE time >= ‘2015-08-18T00:00:00Z‘ AND time Results: -------------- time

SC GROUP by SNO have Count (*) >=2 and min (grade) >=60--8, query the number of students who took 2 courses, the course number and results, the results of the query in descending order by grade.Select Sno,cno,grade from SC where cno=2 order by grade DESC--9, professional names and numbers of professionals with less than 2 professional enquiries.Select Sdept,count (*) as number from student group by Sdept have COUNT (sdept) --10, query the name of female students, professional names, results by

element in S, not an element in TS.symmetric_difference (t) s ^ t symmetric differential operation: elements in S or T, but not s and T are commonThe ElementsS.copy () Copy operation: Returns a (shallow copy) copy of SFor mutable collections onlyS.update (t) s |= T (Union) Modify operation: Add a member of T to the SS.intersection_update (t) s = T intersection modification operation: s includes only members of S and TS.difference_update (t) s-= t Difference modification operation: s includes me