Slow query - Multiple joins and a lot of data

Question

I'm sure there is a better way I could be doing this. I have three main tables with large amounts of data to run through: records_main, sales, and appointments. Each with close to 20,000 records.

I need to join these three tables as well as a few others that arn't two large.

    $SQL = "SELECT DISTINCT appointments.id AS aid, appointments.date, appointments.estimate_price, appointments.next_action, appointments.next_action_date, appointments.result, appointments.result_type, appointments.notes,
customer.id AS cid, customer.homeowner1_fname, customer.homeowner1_lname, customer.address, customer.city, customer.state, customer.zipcode, customer.phone1, customer.phone1_type, customer.phone2, customer.phone2_type, customer.phone3, customer.phone3_type, customer.phone4, customer.phone4_type, customer.phone5, customer.phone5_type, customer.lead_source, customer.lead_category, customer.primary_interest, customer.secondary_interest, customer.additional_interest1, customer.additional_interest2,
originator.employee_id AS originator_employee_id,originator.fname AS originator_fname,originator.lname AS originator_lname,
setter.employee_id AS setter_employee_id,setter.fname AS setter_fname,setter.lname AS setter_lname,
resetter.employee_id AS resetter_employee_id, resetter.fname AS resetter_fname, resetter.lname AS resetter_lname,
salesrep.employee_id AS salesrep_employee_id, salesrep.fname AS salesrep_fname, salesrep.lname AS salesrep_lname,
salesrep2.employee_id AS salesrep2_employee_id, salesrep2.fname AS salesrep2_fname, salesrep2.lname AS salesrep2_lname
FROM
core_records_appointments as appointments
INNER JOIN core_records_main as customer ON appointments.customer = customer.id
LEFT JOIN core_employees_main as originator ON appointments.originator = originator.id
LEFT JOIN core_employees_main as setter ON appointments.setter = setter.id
LEFT JOIN core_employees_main as resetter ON appointments.resetter = resetter.id
LEFT JOIN core_employees_main as salesrep ON appointments.sales_representative = salesrep.id
LEFT JOIN core_employees_main as salesrep2 ON appointments.sales_representative2 = salesrep2.id
 ";

This takes a few seconds but finally does load. The last join I put though seems to break the query together:

LEFT JOIN core_records_sales as sales ON appointments.day = sales.day_sold AND appointments.customer = sales.customer

After this I have a limit set and a group by

Anything I can do to improve this? I am using this with jqgrid, not sure if that helps

Answer 1

As a first approach, try to execute the query on the database using the EXPLAIN syntax. This will give you an analysis of the statement and tells you, if it uses indexes at all. If it doesn't use indexes or not enough indexes, try adding them to the tables.

Answer 2

Have you tried giving index on all the columns you are LEFT JOINing on?

TRY giving index to all these if they are not already declared as index