What is the proper syntax to alias a join that contains a subquery? - tsql

I am trying to alias a JOIN that has a subquery.
RIGHT OUTER JOIN
(
SELECT FieldA, FieldB
FROM Table1
JOIN Table2
ON Table1.WellId = Table2.WellId
) AS wi
AS MProd
ON Units.RS_Unit_Name = RTRIM(wi.RS_POOL) + '-' + wi.RS_Field
I get incorrect syntax near 'AS'...
wi is the alias FieldA & FieldB; How do I alias the RIGHT OUTER JOIN?
My original code was:
RIGHT OUTER JOIN TABLE1
AS MProd
ON Units.RS_Unit_Name = RTRIM(wi.RS_POOL) + '-' + wi.RS_Field
which worked fine. I replaced TABLE1 with a subquery which I did in the code sample. I just can't seem to figure out the proper syntax to set MProd as the alias.

The problem is this line of code:
AS wi AS MProd
This is not valid syntax. It can be AS wi or AS MProd, but not AS wi AS MProd.
This is valid:
RIGHT OUTER JOIN
(
SELECT FieldA, FieldB
FROM Table1
JOIN Table2 ON Table1.WellId = Table2.WellId
) AS MProd
ON Units.RS_Unit_Name = RTRIM(MProd.RS_POOL) + '-' + MProd.RS_Field ...
and so is this:
RIGHT OUTER JOIN
(
SELECT FieldA, FieldB
FROM Table1
JOIN Table2 ON Table1.WellId = Table2.WellId
) AS wi
ON Units.RS_Unit_Name = RTRIM(wi.RS_POOL) + '-' + wi.RS_Field ...

Related

Strange Behaviour on Postgresql query

We created a view in Postgres and I am getting strange result.
View Name: event_puchase_product_overview
When I try to get records with *, I get the correct result. but when I try to get specific fields, I get wrong values.
I hope the screens attached here can explain the problem well.
select *
from event_purchase_product_overview
where id = 15065;
select id, departure_id
from event_puchase_product_overview
where id = 15065;
VIEW definition:
CREATE OR REPLACE VIEW public.event_puchase_product_overview AS
SELECT row_number() OVER () AS id,
e.id AS departure_id,
e.type AS event_type,
e.name,
p.id AS product_id,
pc.name AS product_type,
product_date.attribute AS option,
p.upcomming_date AS supply_date,
pr.date_end AS bid_deadline,
CASE
WHEN (pt.categ_id IN ( SELECT unnest(tt.category_ids) AS unnest
FROM ( SELECT string_to_array(btrim(ir_config_parameter.value, '[]'::text), ', '::text)::integer[] AS category_ids
FROM ir_config_parameter
WHERE ir_config_parameter.key::text = 'trip_product_flight.product_category_hotel'::text) tt)) THEN e.maximum_rooms
WHEN (pt.categ_id IN ( SELECT unnest(tt.category_ids) AS unnest
FROM ( SELECT string_to_array(btrim(ir_config_parameter.value, '[]'::text), ', '::text)::integer[] AS category_ids
FROM ir_config_parameter
WHERE ir_config_parameter.key::text = 'trip_product_flight.product_category_flight'::text) tt)) THEN e.maximum_seats
WHEN (pt.categ_id IN ( SELECT unnest(tt.category_ids) AS unnest
FROM ( SELECT string_to_array(btrim(ir_config_parameter.value, '[]'::text), ', '::text)::integer[] AS category_ids
FROM ir_config_parameter
WHERE ir_config_parameter.key::text = 'trip_product_flight.product_category_bike'::text) tt)) THEN e.maximum_bikes
ELSE e.maximum_seats
END AS departure_qty,
CASE
WHEN now()::date > pr.date_end AND po.state::text = 'draft'::text THEN true
ELSE false
END AS is_deadline,
pl.product_qty::integer AS purchased_qty,
pl.comments,
pl.price_unit AS unit_price,
rp.id AS supplier,
po.id AS po_ref,
po.state AS po_state,
po.date_order AS po_date,
po.user_id AS operator,
pl.po_state_line AS line_status
FROM event_event e
LEFT JOIN product_product p ON p.related_departure = e.id
LEFT JOIN product_template pt ON pt.id = p.product_tmpl_id
LEFT JOIN product_category pc ON pc.id = pt.categ_id
LEFT JOIN purchase_order_line pl ON pl.product_id = p.id
LEFT JOIN purchase_order po ON po.id = pl.order_id
LEFT JOIN purchase_order_purchase_requisition_rel prr ON prr.purchase_order_id = po.id
LEFT JOIN purchase_requisition pr ON pr.id = prr.purchase_requisition_id
LEFT JOIN res_partner rp ON rp.id = po.partner_id
LEFT JOIN ( SELECT p_1.id AS product_id,
pav.name AS attribute
FROM product_product p_1
LEFT JOIN product_attribute_value_product_product_rel pa ON pa.prod_id = p_1.id
LEFT JOIN product_attribute_value pav ON pav.id = pa.att_id
LEFT JOIN product_attribute pat ON pat.id = pav.attribute_id
WHERE pat.name::text <> ALL (ARRAY['Date'::character varying, 'Departure'::character varying]::text[])) product_date ON product_date.product_id = p.id
WHERE (p.id IN ( SELECT DISTINCT mrp_bom_line.product_id
FROM mrp_bom_line)) AND p.active
ORDER BY e.id, pt.categ_id, p.id;
If I add new event_event or new product_product I'll get a new definition of row_number in my view, then the column ID of my view is not stable.
at least you can't use row_number as Id of the view,
If you insist to use row_number, you can use the Order By "creation DATE" by this way all new records will be as last lines in the view and this will not change the correspondency between ID (row_number) and other columns.
Hope that helps !
Very likely the execution plan of your query depends on the columns you select. Compare the execution plans!
Your id is generated using the row_number window function. Now window functions are executed before the ORDER BY clause, so the order will depend on the execution plan and hence on the columns you select.
Using row_number without an explicit ordering doesn't make any sense.
To fix that, don't use
row_number() OVER ()
but
row_number() OVER (ORDER BY e.id, pt.categ_id, p.id)
so that you have a reliable ordering.
In addition, you should omit the ORDER BY clause at the end.

SQL Update query explanation

I would appreciate it if someone can explain me how the piece of code below works internally. For example, how the order of conditions is evaluated.
update br set ScannedId =
(
select top 1 Id from table1 sp (nolock)
inner loop join table2 cp (nolock) ON (sp.CPId = cp.CPID)
inner loop join table3 c (nolock) ON (cp.CID = c.CId and c.endDate >= sp.CreatedDate and c.startDate <= sp.CreatedDate ) `enter code here`
inner loop join table4 cc (nolock) ON (c.CChannelID =`enter code here` cc.CChannelID)
where (sp.UserId is null or sp.UserId = br.UserId)
and ((sp.Email = br.UserEmail)
or (sp.fName like br.UFName + '%' and sp.LName like br.ULName + '%' and sp.sHash = br.uHash)
or (sp.fName like br.UFName + '%' and sp.Addrs = br.UOAddrs and sp.ZC = br.UOZ and sp.sHash = br.uHash))
order by cc.Rank, c.Rank, cp.Rank, sp.EDate desc, sp.CreatedDate desc
)
from channelnewlogic br where userId = 3637217
Rows in channelnewlogic get their ScannedId column values updated according to the result of the inner select.

Relationship not defined with my pgsql Join

I am new to this and haven't been able to find the proper syntax for my table join...
SELECT
DISTINCT on (date (billing.starttime))
medias.name,
date (billing.starttime),
Count(distinct (billing.starttime)) as "# Plays",
Count(distinct(billing.playerid)) as "# Stores"
FROM
public.billing,
public.medias
JOIN ????? on billing.mediaitemid = medias.id
WHERE
medias.name LIKE any (array['COMM_7032%']) and
billing.starttime >= date('2017-04-26') and
billing.starttime < date('2017-05-01')
GROUP BY
date (billing.starttime),
medias.name
ORDER BY
date (billing.starttime)
I am not sure what fits where the ????? are. Everything that I have tried states that the relationship does not exist.
It should go:
...
FROM
public.billing JOIN public.medias on billing.mediaitemid = medias.id
WHERE
...
the syntax is
[table1] join [table2] on [condition]
from
public.billing b
inner join
public.medias m on b.mediaitemid = m.id

Avoiding Order By in T-SQL

Below sample query is a part of my main query. I found SORT operator in below query is consuming 30% of the cost.
To avoid SORT, there is need of creation of Indexes. Is there any other way to optimize this code.
SELECT TOP 1 CONVERT( DATE, T_Date) AS T_Date
FROM TableA
WHERE ID = r.ID
AND Status = 3
AND TableA_ID >ISNULL((
SELECT TOP 1 TableA_ID
FROM TableA
WHERE ID = r.ID
AND Status <> 3
ORDER BY T_Date DESC
), 0)
ORDER BY T_Date ASC
Looks like you can use not exists rather than the sorts. I think you'll probably get a better performance boost by use a CTE or derived table instead of the a scalar subquery.
select *
from r ... left outer join
(
select ID, min(t_date) as min_date from TableA t1
where status = 3 and not exists (
select 1 from TableA t2
where t2.ID = t1.ID
and t2.status <> 3 and t2.t_date > t1.t_date
)
group by ID
) as md on md.ID = r.ID ...
or
select *
from r ... left outer join
(
select t1.ID, min(t1.t_date) as min_date
from TableA t1 left outer join TableA t2
on t2.ID = t1.ID and t2.status <> 3
where t1.status = 3 and t1.t_date < t2.t_date
group by t1.ID
having count(t2.ID) = 0
) as md on md.ID = r.ID ...
It also appears that you're relying on an identity column but it's not clear what those values mean. I'm basically ignoring it and using the date column instead.
Try this:
SELECT TOP 1 CONVERT( DATE, T_Date) AS T_Date
FROM TableA a1
LEFT JOIN (
SELECT ID, MAX(TableA_ID) AS MaxAID
FROM TableA
WHERE Status <> 3
GROUP BY ID
) a2 ON a2.ID = a1.ID AND a1.TableA_ID > coalesce(a2.MAXAID,0)
WHERE a1.ID = r.ID AND a1.Status = 3
ORDER BY T_Date ASC
The use of TOP 1 in combination with the unexplained r alias concern me. There's almost certainly a MUCH better way to get this data into your results that doesn't involve doing this in a sub query (unless this is for an APPLY operation).

Lateral query syntax

I'm trying to get lateral to work in a Postgres 9.5.3 query.
select b_ci."IdOwner",
ci."MinimumPlaces",
ci."MaximumPlaces",
(select count(*) from "LNK_Stu_CI" lnk
where lnk."FK_CourseInstanceId" = b_ci."Id") as "EnrolledStudents",
from "Course" c
join "DBObjectBases" b_c on c."Id" = b_c."Id"
join "DBObjectBases" b_ci on b_ci."IdOwner" = b_c."Id"
join "CourseInstance" ci on ci."Id" = b_ci."Id",
lateral (select ci."MaximumPlaces" - "EnrolledStudents") x
I want the right-most column to be the result of "MaximumPlaces" - "EnrolledStudents" for that row but am struggling to get it to work. At the moment PG is complaining that "EnrolledStudents" does not exist - which is exactly the point of "lateral", isn't it?
select b_ci."IdOwner",
ci."MinimumPlaces",
ci."MaximumPlaces",
(select count(*) from "LNK_Stu_CI" lnk
where lnk."FK_CourseInstanceId" = b_ci."Id") as "EnrolledStudents",
lateral (select "MaximumPlaces" - "EnrolledStudents") as "x"
from "Course" c
join "DBObjectBases" b_c on c."Id" = b_c."Id"
join "DBObjectBases" b_ci on b_ci."IdOwner" = b_c."Id"
join "CourseInstance" ci on ci."Id" = b_ci."Id"
If I try inlining the lateral clause (shown above) in the select it gets upset too and gives me a syntax error - so where does it go?
Thanks,
Adam.
You are missing the point with LATERAL. It can access columns in tables in the FROM clause, but not aliases defined in SELECT clause.
If you want to access alias defined in SELECT clause, you need to add another query level, either using a subquery in FROM clause (AKA derived table) or using a CTE (Common Table Expression). As CTE in PostgreSQL acts as an optimization fence, I strongly recommend going with subquery in this case, like:
select
-- get all columns on the inner query
t.*,
-- get your new expression based on the ones defined in the inner query
t."MaximumPlaces" - t."EnrolledStudents" AS new_alias
from (
select b_ci."IdOwner",
ci."MinimumPlaces",
ci."MaximumPlaces",
(select count(*) from "LNK_Stu_CI" lnk
where lnk."FK_CourseInstanceId" = b_ci."Id") as "EnrolledStudents",
from "Course" c
join "DBObjectBases" b_c on c."Id" = b_c."Id"
join "DBObjectBases" b_ci on b_ci."IdOwner" = b_c."Id"
join "CourseInstance" ci on ci."Id" = b_ci."Id"
) t