I have arrived at a query that gives me what I want but it is not efficient and takes over 45 seconds to execute. How can I modify to make this quicker?
SELECT *
FROM (SELECT DISTINCT email,
title,
first_name,
last_name,
'chauntry' AS source,
post_code AS postcode
FROM chauntry
WHERE mailing_indicator = 1) AS x
LEFT JOIN (SELECT email,
Avg(amount_paid) AS avg_paid,
Count(*) AS no_times_booked,
Count(DISTINCT( Month(added) )) AS unique_months
FROM chauntry
WHERE added >= Now() - INTERVAL 1 year
GROUP BY email) AS y
ON x.email = y.email
here are the data fields
here are the column headings I am after
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