SQL Statement Running Slow - Any Ideas? - mysql

Question

Not sure what's going on with the below statement. It's taking upwards of 5 minutes to run - it only started to show a real slowdown when I wrapped the main statement in a select and aliased it as temp, but doing that has never slowed down any of my other SQL. Any ideas? I'm on MySQL.
select *
from (
select emp.company
, emp.employee
, emp.last_name "Last Name"
, emp.first_name "First Name"
, emp.middle_init "Middle Initial"
, trim(last_name) || ', ' || trim(first_name) ||
decode(trim(middle_init),'','',' '|| trim(middle_init)|| '.') "Full Name"
, emp.emp_status
, emp.work_country "Country"
, (select
(Case pgs.group_name
when 'HREMEA' then 'EMEA'
when 'HRNAMER' then 'NA'
when 'HRLAMER' then 'LA'
when 'HRAPAC' then'APAC'
end)
from lawson.pgselect pgs
where pgs.begin_value = emp.work_country
and pgs.company = 1
and pgs.group_name in ('HREMEA','HRNAMER','HRLAMER','HRAPAC') ) "Region"
, emp.department "Department"
, (select trim(r_name)
from lawson.deptcode dpt
where company = emp.company
and trim(process_level) = trim(emp.process_level)
and trim(department) = trim(emp.department)) "Department Description"
, emp.job_code "Job Code"
, (select description
from lawson.jobcode jbc
where company = emp.company
and job_code = emp.job_code) "Job Title"
, emp.supervisor
, (select trim(last_name) || ', ' || trim(first_name) ||
decode(trim(middle_init),'','',' '|| trim(middle_init)|| '.')
from lawson.employee supv
where supv.company = 1
and supv.position = emp.supervisor
and term_date = '01-JAN-1700') "Supervisor Name"
, (select a_field
from lawson.hrempusf
where company = emp.company and employee = emp.employee
and field_key = '99') "Alt Mgr"
, (select a_field
from lawson.hrempusf
where company = emp.company and employee = emp.employee
and field_key = '79') "TE Proxy Approver"
, (select a_field
from lawson.hrempusf
where company = emp.company and employee = emp.employee
and field_key = '76') "Time Entry Proxy 1"
, (select a_field
from lawson.hrempusf
where company = emp.company and employee = emp.employee
and field_key = '77') "Time Entry Proxy 2"
from lawson.employee emp
where term_date = '01-JAN-1700'
) temp
where temp."TE Proxy Approver" <> ' '
or temp."Time Entry Proxy 1" <> ' '
or temp."Time Entry Proxy 2" <> ' '

Answer 1

Replace Sub queries by join, and make sure that the tables has indexes

Answer 2

A fast review of your query:
too many sub queries, replace them by a join
missing a index on field_key, and term_date
no need for temp sub query, move the where into your main query (less data in your joins)