Is it possible to calculate an avarage based on the cusomer_id (off_klant_id) I want the avarege of all the entrys of an customer and number of orders.
Code:
$sql = "SELECT
off.offerte AS off_offerte,
off.klant_id AS off_klant_id,
off.ref_klant AS off_ref_klant,
off.datum_dossier AS off_datum_dossier,
off.datum_offerte AS off_datum_offerte,
off.bedrag AS off_bedrag,
off.plasma AS off_plasma,
off.water AS off_water,
off.laser AS off_laser,
off.knip_zet AS off_knip_zet,
off.handel AS off_handel,
off.dikte AS off_dikte,
off.materiaal AS off_materiaal,
off.omschrijving AS off_omschrijving,
off.status_id AS off_status_id,
off.reden_vervallen AS off_reden_vervallen,
off.datum_vervallen AS off_datum_vervallen,
off.archief_doos AS archief_doos,
adr.klantnaam AS adr_klantnaam,
ordnr.ordernummer AS ordnr_ordernummer,
ordnr.datum_order AS ordnr_datum_order,
ordnr.datum_leveren AS ordnr_datum_leveren,
fac.factuurnummer AS fac_factuurnummer,
fac.datum_verzonden AS fac_datum_verzonden,
fac.datum_betaald AS fac_datum_betaald,
st.id AS st_id,
st.status AS st_status
FROM offertenummers AS off
LEFT OUTER JOIN adressen AS adr
ON adr.id = off.klant_id
LEFT OUTER JOIN ordernummers AS ordnr
ON ordnr.offerte_id = off.offerte
LEFT OUTER JOIN factuurnummers AS fac
ON fac.offerte_id = off.offerte
LEFT OUTER JOIN status AS st
ON st.id = off.status_id
ORDER BY off.offerte DESC
LIMIT $currentRecord, $recordsPerPage";