Dependent Origination

sql count, sort and group

Posted on: October 26, 2011

My sql knowledge has stayed roughly the same over the years — mostly select’s 🙂 I have resolved to know more about SQL, like at least can work out those interview questions that ask you to find duplicates from a db table 🙂

Here is one example (easy) I have worked out today.

mysql> select column_name, count(*) as c from table_name group by column_name order by c DESC;

This can group all the possible values of a column and count how many rows with each of those values and show the counts in descending order.

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