I have a question on sql desgin.
Context:
I have a table called t_master and 13 other tables (lets call them a,b,c... for simplicity) where it needs to compared.
Logic:
t_master will be compared to table 'a' where t_master.gen_val =
a.value.
If record exist in t_master, retrieve t_master record, else retrieve 'a' record.
I do not need to retrieve the records if it exists in both tables (t_master and a) - XOR condition
Repeat this comparison with the remaining 12 tables.
I have some idea on doing this, using WITH to subquery the non-master tables (a,b,c...) first with their respective WHERE clause.
Then use XOR statement to retrieve the records.
Something like
WITH a AS (SELECT ...),
b AS (SELECT ...)
SELECT field1,field2...
FROM t_master FULL OUTER JOIN a FULL OUTER JOIN b FULL OUTER JOIN c...
ON t_master.gen_value = a.value
WHERE ((field1 = x OR field2 = y ) AND NOT (field1 = x AND field2 = y))
AND ....
.
.
.
.
Seeing that I have 13 tables that I need to full outer join, is there a better way/design to handle this?
Otherwise I would have at least 2*13 lines of WHERE clause which I'm not sure if that will have impact on the performance as t_master is sort of a log table.
**Assume I cant change any schema.
Currently I'm not sure if this SQL will working correctly yet, so I'm hoping someone can guide me in the right direction regarding this.
update from used_by_already's suggestion:
This is what I'm trying to do (comparison between 2 tables first, before I add more, but I am unable to get values from ATP_R.TBL_HI_HDR HI_HDR as it is in the NOT EXISTS subquery.
How do i overcome this?
SELECT LOG_REPO.UNIQ_ID,
LOG_REPO.REQUEST_PAYLOAD,
LOG_REPO.GEN_VAL,
LOG_REPO.CREATED_BY,
TO_CHAR(LOG_REPO.CREATED_DT,'DD/MM/YYYY') AS CREATED_DT,
HI_HDR.HI_NO R_VALUE,
HI_HDR.CREATED_BY R_CREATED_BY,
TO_CHAR(HI_HDR.CREATED_DT,'DD/MM/YYYY') AS R_CREATED_DT
FROM ATP_COMMON.VW_CMN_LOG_GEN_REPO LOG_REPO JOIN ATP_R.TBL_HI_HDR HI_HDR ON LOG_REPO.GEN_VAL = HI_HDR.HI_NO
WHERE NOT EXISTS
(SELECT NULL
FROM ATP_R.TBL_HI_HDR HI_HDR
WHERE LOG_REPO.GEN_VAL = HI_HDR.HI_NO
)
UNION ALL
SELECT LOG_REPO.UNIQ_ID,
LOG_REPO.REQUEST_PAYLOAD,
LOG_REPO.GEN_VAL,
LOG_REPO.CREATED_BY,
TO_CHAR(LOG_REPO.CREATED_DT,'DD/MM/YYYY') AS CREATED_DT,
HI_HDR.HI_NO R_VALUE,
HI_HDR.CREATED_BY R_CREATED_BY,
TO_CHAR(HI_HDR.CREATED_DT,'DD/MM/YYYY') AS R_CREATED_DT
FROM ATP_R.TBL_HI_HDR HI_HDR JOIN ATP_COMMON.VW_CMN_LOG_GEN_REPO LOG_REPO ON HI_HDR.HI_NO = LOG_REPO.GEN_VAL
WHERE NOT EXISTS
(SELECT NULL
FROM ATP_COMMON.VW_CMN_LOG_GEN_REPO LOG_REPO
WHERE HI_HDR.HI_NO = LOG_REPO.GEN_VAL
)
Full outer joins used to exclude all matching rows can be an expensive query. You don't supply much detail, but perhaps using NOT EXISTS would be simpler and maybe it will produce a better explain plan. Something along these lines.
select
cola,colb,colc
from t_master m
where not exists (
select null from a where m.keycol = a.fk_to_m
)
and not exists (
select null from b where m.keycol = b.fk_to_m
)
and not exists (
select null from c where m.keycol = c.fk_to_m
)
union all
select
cola,colb,colc from a
where not exists (
select null from t_master m where a.fk_to_m = m.keycol
)
union all
select
cola,colb,colc from b
where not exists (
select null from t_master m where b.fk_to_m = m.keycol
)
union all
select
cola,colb,colc from c
where not exists (
select null from t_master m where c.fk_to_m = m.keycol
)
You could union the 13 a,b,c ... tables to simplify the coding, but that may not perform so well.
Related
My query should stop inserting values, as the not exists statement is satisfied (I have checked both tables) and matching incidents exist in both tables, any ideas why values are still being returned?
Here is the code:
INSERT INTO
odwh_system.ead_incident_credit_control_s
(
incident
)
SELECT DISTINCT
tp.incident
FROM
odwh_data.ead_incident_status_audit_s ei
INNER JOIN odwh_data.ead_incident_s tp ON ei.incident=tp.incident
WHERE
ei.status = 6
OR
ei.status = 7
AND NOT EXISTS
(
SELECT
true
FROM
odwh_system.ead_incident_credit_control_s ead
WHERE
ead.incident = tp.incident
)
AND EXISTS
(
SELECT
true
FROM
odwh_work.ead_incident_tp_s tp
WHERE
tp.incident = ei.incident
);
dont reuse table aliases
use sane aliases
avoid AND/OR conflicts; prefer IN()
INSERT INTO odwh_system.ead_incident_credit_control_s (incident)
SELECT -- DISTINCT
tp.incident
FROM odwh_data.ead_incident_s dtp
WHERE NOT EXISTS (
SELECT *
FROM odwh_system.ead_incident_credit_control_s sic
WHERE sic.incident = dtp.incident
)
AND EXISTS (
SELECT *
FROM odwh_work.ead_incident_tp_s wtp
JOIN odwh_data.ead_incident_status_audit_s dis ON wtp.incident = dis.incident AND dis.status IN (6 ,7)
WHERE wtp.incident = dtp.incident
);
Let's say I have a table events with structure:
id
value_array
XXXX
[a,b,c,d]
...
...
I have a second table values_of_interest with structure:
value
x
y
z
a
I want to find id's that have any of the values found in values_of_interest. All else equal, what would be the most performant SQL to make this happen? (I am using BigQuery, but feel free to answer more generally)
My current thought is:
SELECT
DISTINCT e.id
FROM
events e, values_of_interest vi
WHERE
EXISTS(
SELECT
value
FROM
UNNEST(e.value_array) value
JOIN
vi ON vi.value = e.value
)
Few quick options for BigQuery Standard SQL
Option 1
select id
from `project.dataset.events`
where exists (
select 1
from `project.dataset.values_of_interest`
where value in unnest(value_array)
)
Option 2
select id
from `project.dataset.events` t
where (
select count(1)
from t.value_array as value
join `project.dataset.values_of_interest`
using(value)
) > 0
I would write this using exists and a join:
select e.id
from `project.dataset.events` e
where exists (select 1
from unnest(e.value_array) val join
`project.dataset.values_of_interest` voi
on val = voi.value
);
I have a query that is using a temp table to insert some data then another select from to extract distinct results. That query by it self was fine but now with entity-framework it is causing all kinds of unexpected errors at the wrong time.
Is there any way I can rewrite the query not to use a temp table? When this is converted into a stored procedure and in entity framework the result set is of type int which throws an error:
Could not find an implementation of the query pattern Select not found.
Here is the query
Drop Table IF EXISTS #Temp
SELECT
a.ReceiverID,
a.AntennaID,
a.AntennaName into #Temp
FROM RFIDReceiverAntenna a
full join Station b ON (a.ReceiverID = b.ReceiverID) and (a.AntennaID = b.AntennaID)
where (a.ReceiverID is NULL or b.ReceiverID is NULL)
and (a.AntennaID IS NULL or b.antennaID is NULL)
select distinct r.ReceiverID, r.ReceiverName, r.receiverdescription
from RFIDReceiver r
inner join #Temp t on r.ReceiverID = t.ReceiverID;
No need for anything fancy, you can just replace the reference to #temp with an inner sub-query containing the query that generates #temp e.g.
select distinct r.ReceiverID, r.ReceiverName, r.receiverdescription
from RFIDReceiver r
inner join (
select
a.ReceiverID,
a.AntennaID,
a.AntennaName
from RFIDReceiverAntenna a
full join Station b ON (a.ReceiverID = b.ReceiverID) and (a.AntennaID = b.AntennaID)
where (a.ReceiverID is NULL or b.ReceiverID is NULL)
and (a.AntennaID IS NULL or b.antennaID is NULL)
) t on r.ReceiverID = t.ReceiverID;
PS: I haven't made any effort to improve the query overall like Gordon has but do consider his suggestions.
First, a full join makes no sense in the first query. You are selecting only columns from the first table, so you need that.
Second, you can use a CTE.
Third, you should be able to get rid of the SELECT DISTINCT by using an EXISTS condition.
I would suggest:
WITH ra AS (
SELECT ra.*
FROM RFIDReceiverAntenna ra
Station s
ON s.ReceiverID = ra.ReceiverID AND
s.AntennaID = ra.AntennaID)
WHERE s.ReceiverID is NULL
)
SELECT r.ReceiverID, r.ReceiverName, r.receiverdescription
FROM RFIDReceiver r
WHERE EXISTS (SELECT 1
FROM ra
WHERE r.ReceiverID = ra.ReceiverID
);
You can use CTE instead of the temp table:
WITH
CTE
AS
(
SELECT
a.ReceiverID,
a.AntennaID,
a.AntennaName
FROM
RFIDReceiverAntenna a
full join Station b
ON (a.ReceiverID = b.ReceiverID)
and (a.AntennaID = b.AntennaID)
where
(a.ReceiverID is NULL or b.ReceiverID is NULL)
and (a.AntennaID IS NULL or b.antennaID is NULL)
)
select distinct
r.ReceiverID, r.ReceiverName, r.receiverdescription
from
RFIDReceiver r
inner join CTE t on r.ReceiverID = t.ReceiverID
;
This query will return the same results as your original query with the temp table, but its performance may be quite different; not necessarily slower, it can be faster. Just something that you should be aware about.
So my issue here is the 'ON' clause will not meet the delete condition if people get delete out of the source tables. Is there a way to do a outer join on the union to include if anything gets deleted for the delete part to work? This something that would run ever 5 minutes. Sorry if this is a bad example of what im trying to do.
merge into table_one ab
using ( select people,job from table_jobs
where job = 'police'
union
select b.people,b.job from second_table_jobs b
where b.job = 'firefighter') zba
on (ab.people = zba.people)
update
set
ab.job ='firefighter'
where b.people = ab.people
and zba.job <> ab.job
delete where zba.people <> ab.people
when not matched then
insert
(
people,
job
)
values
(
zba.people,
zba.job
)
You can run a separate DELETE statement using NOT EXISTS to keep it clean.
DELETE FROM table_one ab
WHERE NOT EXISTS (SELECT 1
FROM (SELECT people,
job
FROM table_jobs
WHERE job = 'police'
UNION
SELECT b.people,
b.job
FROM second_table_jobs b
WHERE b.job = 'firefighter') zba
WHERE ab.people = zba.people);
I have a select query where I am doing inner joins and in AND clause I am checking like this
AND UPPER (b.a1||b.a2) IN
(
select a.a1||a.a2
from a
where a.a3 =
(
select UPPER(decode('609',null,c.c1,'609'))
from dual
)
)
but so because of || opertaor it is taking more than 2 minutes. Can we have any other solution to this?
How about using EXISTS clause?
AND EXISTS (
SELECT
1
FROM
a
WHERE
a.a3 = (SELECT UPPER(DECODE('609',c.c1,'609')) FROM dual) -- this condition is pretty odd
AND a.a1 = UPPER(b.a1)
AND a.a2 = UPPER(b.a2)
)
Adding Function Based Indexes on UPPER(b.a1) AND UPPER(b.a2) may help as well.
Speaking of that odd condition: (SELECT UPPER(DECODE('609',c.c1,'609')) FROM dual):
Why do you perform a SELECT from dual there?
What you check is - if '609' equals c.c1 ('609') then a.a3 must equal '609', in any other case your SELECT returns NULL, thus no value from table a is returned. So you can just change the entire condition to a.a3 = '609'.
Try with a JOIN
SELECT *
FROM b
JOIN ( select UPPER(a.a1), UPPER(a.a2)
from a
where a.a3 = (select UPPER(decode('609',c.c1,'609')) from dual)
) a
ON UPPER(b.b1) = a.a1
AND UPPER(b.b2) = a.a2
But the problem is when you do UPPER(b.b1) or b1||b2 you cant use the index anymore.
You may need a function index
You don't need to concatenate. In fact: concatenating the values is a bug waiting to happen: consider the the values foob and ar in table b and foo and bar in a - the concatenation treats those as the same tuple although they are not.
You also don't need the select from dual for a constant:
AND (UPPER (b.a1), upper(b.a2)) IN
(
select a.a1. a.a2
from a
where a.a3 = UPPER(decode('609',null,c.c1,'609'))
)
An index on b(a1,a2) can't be used for this, but you can create an index on b (UPPER (b.a1), upper(b.a2)) which would be used.