We have a Issuing Database , where permits are issued. There are 16 tables with row 'EXPIRY' which is datetime. I trying to create TSQL / View which can be queried from all the 16 tables with permits expiring in current month or within 30 days which can be put in excel , as each user has email address, hence the travel office can email the users as forewarning.
SELECT dbo.Table1.EXPIRY ,dbo.Table2.EXPIRY AS Expr1 ,dbo.Table3.EXPIRY AS Expr2 ,dbo.Table4.EXPIRY AS Expr3 ,dbo.Table5.EXPIRY AS Expr4
FROM dbo.Table1
INNER JOIN dbo.Table2 ON dbo.Table1.ID = dbo.Table2.ID
INNER JOIN dbo.Table3 ON dbo.Table1.ID = dbo.Table3.ID
INNER JOIN dbo.Table4 ON dbo.Table1.ID = dbo.Table4.ID
INNER JOIN dbo.Table5 ON dbo.Table1.ID = dbo.Table5.ID
I am Junior DBA, hence just learning TSQL. I was wondering if any one can help
What you need first is to find all the Tables which have an expiry field, so you should look them up in the system Tables. Then dynamicly form your querys and execute them.
declare #sql varchar(max);
select #sql = CONCAT(#sql, 'select email from dbo.', t.Name, `;`)
from sys.columns c
join sys.tables t on c.object_id = t.object_id
where c.name like 'EXPIRY%'
exec(#sql)
Right now this sql would give you x Results, depending on how many tables you have with expiry, you will need to apply the filters and if you want to use a view union all inside the CONCAT
Related
This is a current postgres query I have:
sql = """
SELECT
vms.campaign_id,
avg(vms.open_rate_uplift) as open_rate_average,
avg(vms.click_rate_uplift) as click_rate_average,
avg(vms.conversion_rate_uplift) as conversion_rate_average,
avg(cms.incremental_opens),
avg(cms.incremental_clicks),
avg(cms.incremental_conversions)
FROM
experiments.variant_metric_snapshot vms
INNER JOIN experiments.campaign_metric_snapshot cms ON vms.campaign_id = cms.campaign_id
WHERE
vms.campaign_id IN %(campaign_ids)s
GROUP BY
vms.campaign_id
"""
whereby I get the average incremental_opens, incremental_clicks, and incremental_conversions per campaign group from the cms table. However, instead of the average, I want the most recent values for the 3 fields. See the cms table screenshot below - I want the values from the record with the greatest (i.e. most recent) event_id (instead of an average for all records) for a given group).
How can I do this? Thanks
It sounds like you want a lateral join.
FROM
experiments.variant_metric_snapshot vms
CROSS JOIN LATERAL (select * from experiments.campaign_metric_snapshot cms where vms.campaign_id = cms.campaign_id order by event_id desc LIMIT 1) cms
WHERE...
If you are after a quick and dirty solution you can use array_agg function with minimal change to your query.
SELECT
vms.campaign_id,
avg(vms.open_rate_uplift) as open_rate_average,
avg(vms.click_rate_uplift) as click_rate_average,
avg(vms.conversion_rate_uplift) as conversion_rate_average,
(array_agg(cms.incremental_opens ORDER BY cms.event_id DESC))[1] AS incremental_opens,
..
FROM
experiments.variant_metric_snapshot vms
INNER JOIN experiments.campaign_metric_snapshot cms ON vms.campaign_id = cms.campaign_id
WHERE
vms.campaign_id IN %(campaign_ids)s
GROUP BY
vms.campaign_id;
I'm working with Hibernate thus HQL, linked to a PostgreSQL database.
I have a table users and a table teams that are linked with a ManyToMany condition throught the table teams_users.
I'd like to update or select the table team so the property usersCount takes the amount of users belonging to a team.
I do not want to add a #Formula to my Entity Class, because I don't want it to be executed all the time, that's too wastful on big JOIN FETCH query where I do not need the count.
I other words, I'd like to find the HQL equivalent of the following PSQL query
UPDATE teams t
SET users_count = (SELECT COUNT(ut.*)
FROM teams t1
LEFT JOIN teams_users tu
ON t1.id = tu.team_id
WHERE t1.id = t.id
GROUP BY t1.id);
OR
An equivalent of the following
SELECT t.*, count(tu.*) AS users_count
FROM teams t
LEFT JOIN teams_users tu
ON t.id = tu.team_id
GROUP BY t.id;
Unsuccessful tries (to get an idea)
UPDATE Team t SET
t.usersCount = COUNT(t.users)
UPDATE Team t SET
t.usersCount = (SELECT COUNT(t1.users) FROM Team t1 WHERE t1.id = t.id)
SELECT t, count(t.users) AS t.usersCount
FROM Team t
I've found the solution for the UPDATE query.
It simply is
UPDATE Team t
SET t.usersCount = (SELECT COUNT(u) from t.users u)
It makes an extra join on the table users whilst the table teams_users would be enought but well... It works.
If anyone has ths solution for the SELECT one, I'm still curious !
Running out of spool space wondering if the query can be optimized.
I've tried running a DISTINCT and UNION ALL, Group By doesn't make sense.
SELECT DISTINCT T1.EMAIL, T2.BILLG_STATE_CD, T2.BILLG_ZIP_CD
FROM
(SELECT EMAIL
FROM CAT
UNION ALL
SELECT EMAIL
FROM DOG
UNION ALL
SELECT email As EMAIL
FROM MOUSE) As T1
LEFT JOIN HAMSTER As T2 ON T1.EMAIL =T2.EMAIL_ADDR;
I will need to do this same type of data pull often, looking for a viable solution other than doing three separate joins.
I need to union multiple tables (T1) and join columns from another table (T2) on (T1).
WHERE T2.ord_creatd_dt > DATE '2019-01-01' and T2.ord_creatd_dt < DATE '2019-11-08'
Postgres allows you to create a table using inheritance. We have a design where we have 1400 tables that inherit from one main table. These tables are for each of our vendor's inventory.
When I want to query stock for a vendor, I just query the main table. When running Explain, the explanation says that it is going through all 1400 indexes and quite a few of the inherited tables. This causes the query to run very slowly. If I query only the vendor's stock table, I cut the query time to less than 50% of the time by querying the main table.
We have a join on another table that pulls identifiers for the vendor's partner vendors and we also want to query their stock. Example:
SELECT
(select m2.company from sup.members m2 where m2.id = u.id) as company,
u.id,
u.item,
DATE_PART('day', CURRENT_TIMESTAMP - u.datein::timestamp) AS daysinstock,
u.grade as condition,
u.stockno AS stocknumber,
u.ic,
CASE WHEN u.rprice > 0 THEN
u.rprice
ELSE
NULL
END AS price,
u.qty
FROM pub.net u
LEFT JOIN sup.members m1
ON m1.id = u.id OR u.id = any(regexp_split_to_array(m1.partnerslist,','))
WHERE u.ic in ('01036') -- part to query
AND m1.id = 'N40' -- vendor to query
The n40_stock table has stock for the vendor with id = N40 and N40's partner vendors (partnerslist) are G01, G06, G21, K17, N49, V02, M16 so I would also want
to query the g01_stock, g06_stock, g21_stock, k17_stock, n49_stock, v02_stock, and m16_stock tables.
I know about the ONLY clause but is there away to modify this query to get the data from ONLY the specific inherited tables?
Edit
This decreases the time to under 800ms, but I'd like it less:
WITH cte as (
SELECT partnerslist as a FROM sup.members WHERE id = 'N40'
)
SELECT
(select m2.company from sup.members m2 where m2.id = u.id) as company,
u.id,
u.item,
DATE_PART('day', CURRENT_TIMESTAMP - u.datein::timestamp) AS daysinstock,
u.grade as condition,
u.stockno AS stocknumber,
u.ic,
CASE WHEN u.rprice > 0 THEN
u.rprice
ELSE
NULL
END AS price,
u.qty
FROM pub.net u
WHERE u.ic in ('01036') -- part to query
AND u.id = any(regexp_split_to_array('N40,'||(select a from cte), ','))
I cannot retrieve the company from sup.members in the cte because I need the one from the u.id, which is different when the partner changes in the where clause.
Inherited table lookups are based on the actual WHERE clause, which maps to the CHECK table constraint. Simply inheriting tables is not good enough.
https://www.postgresql.org/docs/9.6/static/ddl-partitioning.html
Caveat, you can not use a dynamically created variables where the actual value is not implemented in the raw query. This results in a check of all inherited tables.
I'm building a query that needs data from 5 tables.
I've been told by a DBA in the past that specifying a list of columns vs getting all columns (*) is preferred from some performance/memory aspect.
I've also been told that the database performs a JOIN operation behind the scenes when there's a list of tables in the FROM clause, to create one table (or view).
The existing database has very little data at the moment, as we're at a very initial point. So not sure I can measure the performance hit in practice.
I am not a database pro. I can get what data I need. The dillema is, at what price.
Added: At the moment I'm working with MS SQL Server 2008 R2.
My questions are:
Is there a performance difference and why, between the following:
a. SELECT ... FROM tbl1, tbl2, tbl3 etc for simplicity? (somehow I feel that this might be a performance hit)
b. SELECT ... FROM tbl1 inner join tbl2 on ... inner join tbl3 on ... etc (would this be more explicit to the server and save on performance/memory)?
c. SELECT ... FROM (select x,y,z from tbl1) as t1 inner join ... etc (would this save anythig? or is it just extra select statements that create more work for the server and for us)?
Is there yet a better way to do this?
Below are two queries that both get the slice of data that I need. One includes more nested select statements.
I apologize if they are not written in a standard form or helplessly overcomplicated - hopefully you can decipher. I try to keep them organized as much as possible.
Insights would be most appreciated as well.
Thanks for checking this out.
5 tables: devicepool, users, trips, TripTracker, and order
Query 1 (more select statements):
SELECT
username,
base.devid devid,
tripstatus,
stops,
stopnumber,
[time],
[orderstatus],
[destaddress]
FROM
((
( SELECT
username,
devicepool.devid devid,
groupid
FROM
devicepool INNER JOIN users
ON devicepool.userid = users.userid
WHERE devicepool.groupid = 1
)
AS [base]
INNER JOIN
(
SELECT
tripid,
[status] tripstatus,
stops,
devid,
groupid
FROM
trips
)
AS [base2]
ON base.devid = base2.devid AND base2.groupid = base.groupid
INNER JOIN
(
SELECT
stopnumber,
devid,
[time],
MAX([time]) OVER (PARTITION BY devid) latesttime
FROM
TripTracker
)
AS [tracker]
ON tracker.devid = base.devid AND [time] = latesttime)
INNER JOIN
(
SELECT
[status] [orderstatus],
[address] [destaddress],
[tripid],
stopnumber orderstopnumber
FROM [order]
)
AS [orders]
ON orders.orderstopnumber = tracker.stopnumber)
Query 2:
SELECT
username,
base.devid devid,
tripstatus,
stops,
stopnumber,
[time],
[orderstatus],
[destaddress]
FROM
((
( SELECT
username,
devicepool.devid devid,
groupid
FROM
devicepool INNER JOIN users
ON devicepool.userid = users.userid
WHERE devicepool.groupid = 1
)
AS [base]
INNER JOIN
trips
ON base.devid = trips.devid AND trips.groupid = base.groupid
INNER JOIN
(
SELECT
stopnumber,
devid,
[time],
MAX([time]) OVER (PARTITION BY devid) latesttime
FROM
TripTracker
)
AS [tracker]
ON tracker.devid = base.devid AND [time] = latesttime)
INNER JOIN
[order]
ON [order].stopnumber = tracker.stopnumber)
Is there a performance difference and why, between the following: a.
SELECT ... FROM tbl1, tbl2, tbl3 etc for simplicity? (somehow I feel
that this might be a performance hit) b. SELECT ... FROM tbl1 inner
join tbl2 on ... inner join tbl3 on ... etc (would this be more
explicit to the server and save on performance/memory)? c. SELECT ...
FROM (select x,y,z from tbl1) as t1 inner join ... etc (would this
save anythig? or is it just extra select statements that create more
work for the server and for us)?
a) and b) should result in the same query plan (although this is db-specific). b) is much preferred for portability and readability over a). c) is a horrible idea, that hurts readability and if anything will result in worse peformance. Let us never speak of it again.
Is there yet a better way to do this?
b) is the standard approach. In general, writing the plainest ANSI SQL will result in the best performance, as it allows the query parser to easily understand what you are trying to do. Trying to outsmart the compiler with tricks may work in a given situation, but does not mean that it will still work when the cardinality or amount of data changes, or the database engine is upgraded. So, avoid doing that unless you are absolutely forced to.