SQL Query with Arithmetic Sub-Queries

Question

I have a simple MYSQL table with about 5 columns or so. The row size of the table changes quite frequently.

One of these columns is named has_error, and is a column that has a value of either 1 or 0.

I want to create a single SQL query that will be the equivalent of the following simple equation:

(Number of rows with has_error = 1/Total number of rows in table) * 100

I can create the individual SQL queries (see below), but not sure how to put it all together.

SELECT COUNT(*) AS total_number_of_rows FROM my_table
SELECT COUNT(*) AS number_of_rows_with_errors FROM My_table WHERE has_error = 1

Gordon Linoff · Accepted Answer · 2015-04-07 23:53:29Z

1

This is easy because you can just use avg(has_error):

SELECT AVG(has_error) * 100
FROM My_table;

answered Apr 7, 2015 at 23:53

Gordon Linoff

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1 Comment

Doh! Not sure why I didn't think of that. Thanks.