How to count number of occurrences for all different values in database column?
I have a Postgre database that has say 10 columns. The fifth column is called column5
. There are 100 rows in the database and possible values of column5
are c5value1, c5value2, c5value3...c5value29, c5value30
. I would like to print out a table that shows how many times each value occurs.
So the table would look like this:
Value(of column5) number of occurrences of the value
c5value1 开发者_StackOverflow中文版 1
c5value2 5
c5value3 3
c5value4 9
c5value5 1
c5value6 1
. .
. .
. .
What is the command that does that?
Group by the column you are interested in and then use count to get the number of rows in each group:
SELECT column5, COUNT(*)
FROM table1
GROUP BY column5
Use the GROUP BY
clause and the COUNT()
aggregate function:
SELECT column5, COUNT(column5) AS Occurences
FROM myTable
GROUP BY column5
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