I have two tables:
Table 1:
employer(id_em, nom_em)
Table 2:
the second one is
travailler(id_em, id_depart, date_chnge)
a certain id_em can have multiple entries in the travailler table but I want only to get a table with the latest entry of id_em, so basically the one with the biggest date.
so the result of my query should be something like this :
(id_em, nom_em, id_depart, date_change)
but only one entry for every id_em, the one that has the latest date
I've tried this but it shows all of them, I don't know what's wrong
SELECT employe.nom_em,
travailler.id_em,
travailler.id_depart,
Max(travailler.date_chnge)
FROM employe
INNER JOIN travailler
ON employe.id_em = travailler.id_em
GROUP BY employe.id_em
Please help!
SELECT
e.nom_em,
t.id_em,
t.id_depart,
t.date_chnge
FROM
employe e
INNER JOIN
travailler t
ON e.id_em=t.id_em
WHERE
t.date_chnge = (select max(tr.date_chnge) from travailler tr where tr.id_em = e.id_em)
Related
I have two tables, Project and Projectnote
There is a one to many relationship between project and projectnote.
I want to be able to list my projects and select the most recent projectnotes based on the id.
Is this possible to do in Mysql query, I can't figure it out.
Thanks for any help!
Edit: so far I have a basic query (below) that joins the two tables. However, this only selects projects where a note exists and I get multiple rows where there are several notes per project.
SELECT `driver_checkins`.*, `driver_trips`.`id` AS `trip_id`, `driver_trips`.`trip_num` AS `trip_num`, `driver_trips`.`status` AS `trip_status`, `driver_trips`.`ride_date` AS `ride_date`, `driver_trips`.`today_date` AS `trip_today_date`, `driver_trips`.`pick_up_time` AS `pick_up_time`, `driver_trips`.`d_time` AS `d_time`, `driver_trips`.`trip_type` AS `trip_type`
FROM `driver_checkins`
LEFT JOIN `driver_trips` ON `driver_trips`.`driver_id` = `driver_checkins`.`driver_id` WHERE `checkin_status` = 1 AND `booking_status` = 0;
Using a GROUP BY clause and the GROUP_CONCAT function should do the trick.
I am assuming that "driver_checkins" is your "Project" table and "driver_trips" is your "Projectnote" table.
SELECT `driver_checkins`.*, GROUP_CONCAT(`driver_trips`.`id`, `driver_trips`.`status` ORDER BY `driver_trips`.id DESC SEPARATOR " --- " LIMIT 3)
FROM `driver_checkins`
LEFT JOIN `driver_trips` ON `driver_trips`.`driver_id` = `driver_checkins`.`driver_id`
WHERE `checkin_status` = 1 AND `booking_status` = 0
GROUP BY `driver_checkins`.id;
This should display id and status for the last 3 driver_trips per driver_checkin, separated by " --- ".
Something to consider: while in many cases ordering by id will work chronologically, it's always better to add a timestamp column (e.g. called created) instead to order by chronologically.
My data set is like so:
Total_Order_Table
Order_no (unique)
Shipped_quantity
Order_Detail_Table
Order_number (not unique)
Quantity_per_bundle
I need to take the sum of Quantity_per_bundle for each order_number from Order_Detail_Table and compare it to the Shipped_quantity.
My idea is an outer join so that my data will look like so:
I need to be able to see quantity discrepancies and if the order number exists in both tables.
Thanks in advance!
Normaly with a FULL OUTER JOIN in sql:
SELECT to.Order_no AS Order_no_Total_Order_Table, od.Order_number AS Order_No_Ordr_detail_Table, SUM(od.Order_number) AS sum_Quanitty_Per_Bundle, od.Order_number
FROM Total_Order_Table AS to
FULL OUTER JOIN Order_Detail_Table AS od ON to.Order_no = od.Order_number
GROUP BY to.Order_no
But FULL OUTER JOIN don't exist in mysql. But you can simulate it : http://www.xaprb.com/blog/2006/05/26/how-to-write-full-outer-join-in-mysql/
Unless I'm missing something subtle in the question, isn't this just as simple as a SELECT query with a join between the tables.
Something along the lines of this should achieve the result:
SELECT tot.Order_no,
odt.Order_no,
SUM(odt.Quantity_per_bundle),
tot.Shipped_quantity
FROM Total_Order_Table tot
LEFT JOIN Order_Detail_Table odt ON odt.Order_Number = tot.Order_Number
GROUP BY tot.Order_no, odt.Order_no, tot.shipped_quantity
(Code not tested in MySQL so forgive errors)
I am trying to create an inner-join MySQL Query of two tables:
'swatchset'
->swatchset_id
->swatchset_name
'swatches'
->swatch_id
->swatch_name
->swatch_hex
->etc...
I currently have one record in the 'swatchset' table:
swatchset_id | swatchset_name
8 default
The 'swatches' table is empty.
I want to get as result the 'swatchset'.'swatchset_name'
I guess I don't understand INNER JOIN very well because this Query results nothing:
SELECT `swatchset`.`swatchset_name`, `swatches`.`swatch_id`, `swatches`.`swatch_name`, `swatches`.`swatch_hex`, `swatches`.`swatch_type` FROM `swatchset`
INNER JOIN `swatches`
ON `swatches`.`f_swatchset_id` = `swatchset`.`swatchset_id`
WHERE `swatchset`.`swatchset_id` = '8';
How can I get at least the found 'swatchset' row as result?
Left outer join will fill with nulls columns of second table when not found:
SELECT `swatchset`.`swatchset_name`, `swatches`.`swatch_id`, `swatches`.`swatch_name`, `swatches`.`swatch_hex`, `swatches`.`swatch_type` FROM `swatchset`
LEFT OUTER JOIN `swatches`
ON `swatches`.`f_swatchset_id` = `swatchset`.`swatchset_id`
WHERE `swatchset`.`swatchset_id` = '8';
inner join doesn't return entries from first table without matching ones in second table
I have a table name as "invoice" which consists of column name "CId"
I have another table name as invoiceclient_details which consists of column name "CId"
So now my question is "what query should i write so that i will get the data of greater "CId" i.e. rows of data which consists of greater "CID"
I have tried like this
SELECT
invoiceclient_details.OrganizationName,
invoiceclient_details.InvoiceNo,
invoiceclient_details.InvoiceDate,
invoiceclient_details.DeliveryNote,
invoiceclient_details.TermsofPayment,
invoiceclient_details.EsugamNo,
invoiceclient_details.OrganizationName,
invoiceclient_details.BuyerOrderNo,
invoiceclient_details.BuyDate,
invoiceclient_details.DispatchDocumentNo,
invoiceclient_details.Dated,
invoiceclient_details.DispatchThrough,
invoiceclient_details.Destination,
invoiceclient_details.TermsofDelivery,
invoiceclient_details.BuyerTin,
invoice.id,
invoice.DescriptionOfGoods,
invoice.Quantity,
invoice.PerUnitPrice,
invoice.TotalPrice,
invoice.VAT14,
invoice.VAT5,
invoice.ServiceTax,
invoice.CST
FROM invoiceclient_details,invoice
WHERE MAX(invoiceclient_details.CId) = MAX(invoice.CId);
But it is showing an error like
"misusage of group function"
Use an INNER JOIN to join the tables on the CId.
SELECT *
FROM invoice i
INNER JOIN invoiceclient_details icd ON i.CId = icd.CId
Try this
select *
from invoice,invoiceclient_details
where
invoice.CId in (Select max(invoiceclient_details.CId) from invoiceclient_details)
and
invoiceclient_details.CId in (Select max(invoiceclient_details.CId) from invoiceclient_details)
I have two table --> tbl_book_details and tbl_table_traking
tbl_book_details has columns bd_book_code,
bd_isbn,
bd_title,
bd_edition,
bd_author,
bd_publisher,
bd_supplier,
bd_page,
bd_price_type,
bd_cost_price,
bd_price,
bd_Tax,
bd_covering,
bd_availability,
bd_keywords,
bd_notes,
bd_details,
bd_news_latter,
bd_etDate,
bd_weight,
bd_expire_date,
bd_status
tbl_table_traking has columns
tt_id,
tt_action,
tt_table,
tt_record_id,
tt_on_date,
tt_user,
tt_status
the process is a trigger is defined on tbl_book_details which in case of insert/modify insert the data in tbl_table_traking for traking when and who has modified the records.
till now i have been using following query which is not a join -->
SELECT
tbl_books_details.bd_book_code AS bkid,
tbl_books_details.bd_isbn,
tbl_books_details.bd_title AS title,
-- This part is what I believe is slowing down my query
(SELECT
tt_on_date
FROM
tbl_table_tracking
WHERE tt_action = 'MODIFY'
AND tt_record_id = tbl_books_details.bd_book_code ORDER BY tt_on_date) AS bd_etdate
it was working fine when the records count were below 3 million, but now script time out is occurring.
I have made the index on tbl_table_traking on 'tt_ondate' and on tt_action,
If there any way i can convert it to a join or improve the performance?
the table traking query is returning the mostrecent date on which the record was modified.
my database is in mysql.
You should be able to do something like this.
SELECT
tbl_books_details.bd_book_code AS bkid,
tbl_books_details.bd_isbn,
tbl_books_details.bd_title AS title,
tbl_table_traking.tt_on_date
FROM
tbl_books_details
INNER JOIN tbl_table_tracking
tbl_books_details.bd_book_code = tbl_table_tracking.tt_record_id
WHERE tt_action = 'MODIFY';
Hope this helps...