Getting the median value from the database

sql median w3schools
median sql server
sql median group by
sql median postgres
median in sql oracle
sqlite median
sql get median of a column
mysql median group by

A median is defined as a number separating the higher half of a data set from the lower half. Query the median of the Northern Latitudes (LAT_N) from STATION and round your answer to decimal places.

Input Format

The STATION table is described as follows:

Field : Type
ID    : NUMBER
CITY  : VARCHAR2(21)
STATE : VARCHAR2(2)
LAT_N : NUMBER
LONG_W: NUMBER

where LAT_N is the northern latitude and LONG_W is the western longitude.

I could only manage to get the row index for the median value with

select floor((count(lat_n)+1)/2) from station;

which is row index 250. The next step is to use this value to extract out the lat_n value at row index 250. How do I transform to SQL?

Here is one option. We can assign a row number, while at the same time computing the total table count. Then, for tables with an even number of records, we can take the average of the middle two records as the median. For odd numbered tables, we can just take the middle record.

WITH cte AS (
    SELECT s.*,
        ROW_NUMBER() OVER (ORDER BY lat_n) rn,
        COUNT(*) OVER () cnt
    FROM station s
)

SELECT AVG(lat_n)
FROM cte
WHERE
    (MOD(cnt, 2) = 0 AND rn IN (FLOOR(cnt/2), FLOOR(cnt/2) + 1)) OR
    (MOD(cnt, 2) = 1 AND rn = FLOOR(cnt/2) + 1);

Demo

Note: For tables with an even number of records, it should be obvious that there is no exact median/middle record. But many statisticians just report the average of the middle pair of records in this case.

How to calculate median value in MySQL using a simple SQL query, Medians are much more difficult for the database to compute, so there We'll do it in SQL and get Postgres to help us find the middle value by  What is a median value? The median of an array of numbers is the value of the middle item in the array, assuming the array is sorted. If the array has an even number of items, the median represents the average of the two middle values in the array. This value is very popular one tries to understand "in which half my value is?".

The simplest method is to use the median() function:

select median(lat_n)
from stations;

You can round the value using functions such as round() or to_char().

Medians in SQL, The simplest method is to use the median() function: select median(lat_n) from stations;. You can round the value using functions such as  how to get median value. 2. Median Value in SQL Server. 3. Median value from group. 4. Median Value. 5. median value in T-sql. 6. The Median Value. 7. Computing Median Values. 8. Calculating Median Value. 9. Median value. 10. Q: Finding median value. 11. SQL to get median value - any ideas?

Easy explanation of the sample median: In individual series (if number of observation is very low) first one must arrange all the observations in order. Then count(n) is the total number of observation in given data.

If n is odd then Median (M) = value of ((n + 1)/2)th item term.

If n is even then Median (M) = value of [(n/2)th item term + (n/2 + 1)th item term]/2

CTE in Sql Server

Query:

declare @cont int,@reccount int,@first int, @second int;
set @reccount=(select COUNT(id) from STATION);
IF @reccount%2=0 --even rows
set @cont=(((@reccount)/2)+(((@reccount)/2)+1))/2; 
ELSE 
set @cont=((select count(id) from station)+1)/2;
--creating CTE
WITH Station_CTE (rowNum, Lat_n)
AS (
select row_number() over(order by lat_n desc) as 'rowNum',lat_n from station
)
SELECT top(1) SUBSTRING(convert(varchar(30),ROUND((scte.lat_n),4)),1,(CHARINDEX('.',ROUND((scte.lat_n),4),1)+4)) from Station s inner join Station_CTE as scte on scte.rowNum =@cont

Expected Output:

83.8913

Getting the median value from the database, How do you find the median of a column in mysql? The median() function returns the median (middle value) of numeric data. When several data points are odd, return the middle data point. When the number of data points is even, a median is interpolated by taking the average of the two middle values.

declare @Position int
set @position = round((select count(LAT_N)/2 from STATION),0)

select convert(decimal(20,4),LAT_N) from STATION
order by LAT_N
offset @position rows
fetch next 1 row only

Simple way to calculate median with MySQL, According to WikiPedia, "median is described as the numerical value This example implements a clever use of OFFSET / FETCH (and not  Some databases (e.g. Oracle, HSQLDB) support a MEDIAN() aggregate function: [code]SELECT MEDIAN(column) FROM table[/code] Some others (Oracle, PostgreSQL 9.4+, Amazon Redshift) support the SQL standard PERCENTILE_DISC() inverse distribution func

Mean Median Mode Formula, Learn about the median value and how to calculate it for a specified dataset by using Calculating the median by using the RANK() function and CTE Nisarg is a SQL Server Database Administrator and Microsoft certified  There is quite a bit of discussion here on calculating median values from a MySQL table. Just search the page for 'median'. As an aside, it strikes me as remiss that there is no built-in function to do this. Median is often more descriptive of central tendency than mean. Access/VBA has the same hole in its function list.

What is the fastest way to calculate the median?, In continuing with this idea, we just need to calculate the median value of this integer to get the following… -- calculating the median using the converted String --  Getting the median value from the database. A median is defined as a number separating the higher half of a data set from the lower half. Query the median of the Northern Latitudes (LAT_N) from STATION and round your answer to decimal places.

Calculate the median by using Transact SQL – {coding}Sight, To get the median, we need to be able to accomplish the following: Obtain the value for the middle-ranked row. DIV is the way to find the quotient in MySQL, the exact way to obtain the quotient may be different with other databases. Finally​  The median value of this set of numbers is 23. (It doesn't matter that some numbers are the same in the list.)

Use SQL to Calculate Median Values., An average is the “middle” value in a set of data values. When talking about or calculating an average, most people consider using the “mean”. Let's use the AdventureWorks2008R2 sample database to explore these  Defination of Median as per Wikipedia : The median is the value separating the higher half of a data sample, a population, or a probability distribution, from the lower half. In simple terms, it may be thought of as the “middle” value of a data set. There is no MEDIAN function in T-SQL.

Comments
  • Which database system? Oracle?SQLS? Postgres? Mysql? etc
  • Welcome to SO! It's a near guarantee that this has been asked before, do please have a search (using google to search this site if necesasary - its' better than SO's built in search) and let us know what you've tried
  • Tagged with oracle based on the usage of the number and varchar2 data types
  • Edge case: For even-numbered tables, the median is usually reported as the mean value of the middle two records.
  • As an aside, it looks like you've dumped the text in from a homework or examwork type exercise, and I don't submit answers for those by default because I don't regard using SO as a homework completion device to be a sensible use of time with regards to your own learning. Do please take a look at techonthenet.com/oracle/functions/median.php though - oracle has a function to do median, and your question as is lacks sufficient detail for anyone other than you (who knows what you want the median per) to complete..
  • This function is only available in Oracle.
  • @Wiebke . . . The question is tagged Oracle.