Speed up SQL nested query - mysql

I have a table called ntr_perf with the following column: data, cos, network, tot_reg, tot_rej.
I need to get the sums of tot_reg and tot_rej for each pair data-cos (I need to take all data-cos pairs and make the sum of the values for all the networks with the same data-cos pair).
I'm using the following MySQL query:
SELECT DISTINCT
data AS d,
cos AS c,
(SELECT SUM(tot_reg) FROM ntr_perf WHERE data=d AND cos=c) AS sumattempts,
(SELECT SUM(tot_rej) FROM ntr_perf WHERE data=d AND cos=c) AS sumrej FROM ntr_perf
It takes a very long time even if the table has only 91.450 rows (the table has a multi-column index data-cos).
Is it possible to speed up the query?


This is exactly what group by is designed for.
Try this:
SELECT data,cos,SUM(tot_reg),SUM(tot_rej) from ntr_perf group by data,cos


You can use this query,
SELECT data AS d, cos AS c,
SUM(tot_reg), SUM(tot_reg) where
data='d' AND cos='c' group by data , cos ;
Hope you got is. Else let me know, will help you


Try this, a group by
SELECT data d,
cos c,
SUM(tot_reg) sumattempts,
SUM(tot_rej) sumrej
FROM ntr_perf
WHERE data = 'd' -- if these are values, put in single quotes
AND cos = 'c' -- if these are values, put in single quotes
GROUP BY data, -- even though aliased, the original name needs to be used on the GROUP BY
cos -- even though aliased, the original name needs to be used on the GROUP BY


this will group your query and filter your sums, as you posted WHERE conditions:
SELECT
data AS d,
cos AS c,
SUM(IIF(data='d' AND cos='c', tot_reg, 0) AS sumattempts,
SUM(IIF(data='d' AND cos='c', tot_rej, 0)) AS sumrej
FROM
ntr_perf
GROUP BY
data,
cos

Related

Expressing two combined conditions in mysql

I have this table with some data that i am interested in. The table is called trades. basically, i want to select all data in that table but this conditions must hold.
trade_session_status="DONE"
(trade_prediction="up" AND trade_result="up" ) OR (trade_prediction="down" AND trade_result="down" )
I have written the whole query like this
select * from trades where trade_session_status="DONE" AND
(trade_prediction="up" AND trade_result="up" ) OR
(trade_prediction="down" AND trade_result="down" )
I want to get all data where trade_session_status is "DONE" and someone predicted up and the result indeed came to be up or someone who predicted down and the result came to be down.
The query returns some data without any error. Is my query expression correct?.

You need to add additional brackets:
select *
from trades
where trade_session_status="DONE"
AND ((trade_prediction="up" AND trade_result="up" )
OR (trade_prediction="down" AND trade_result="down" ))
Alternatively:
select *
from trades
where trade_session_status='DONE'
AND (trade_prediction, trade_result) IN (('up', 'up'),('down', 'down'))

MySQL String Position and Substring sort

Example data to sort:
xy3abc
y3bbc
z3bd
Sort order must be abc, bbc, bd regardless of what is before the numeral.
I tried:
SELECT
*,
LEAST(
if (Locate('0',fcccall) >0,Locate('0',fcccall),99),
if (Locate('1',fcccall) >0,Locate('1',fcccall),99),
if (Locate('2',fcccall) >0,Locate('2',fcccall),99),
if (Locate('3',fcccall) >0,Locate('3',fcccall),99),
if (Locate('4',fcccall) >0,Locate('4',fcccall),99),
if (Locate('5',fcccall) >0,Locate('5',fcccall),99),
if (Locate('6',fcccall) >0,Locate('6',fcccall),99),
if (Locate('7',fcccall) >0,Locate('7',fcccall),99),
if (Locate('8',fcccall) >0,Locate('8',fcccall),99),
if (Locate('9',fcccall) >0,Locate('9',fcccall),99)
) as locationPos,
SUBSTRING(fcccall,locationPos,3) as fccsuffix
FROM memberlist
ORDER BY locationPos, fccsuffix
but locationPos gives me an error on the substring function call

It's not possible to reference that expression by its alias locationPos, within another expression in the same SELECT list.
Replicating the entire expression would be the SQL way to do it. (Yes, it is ugly repeating that entire expression.)
Another (less performant) approach is to use your query (minus the fccsuffix expression) as an inline view. The outer query can reference the assigned locationPos alias as a column name.
As a simple example:
SELECT v.locationPos
FROM ( SELECT 'my really big expression' AS locationPos
FROM ...
) v
This approach of using an inline view ("derived table") can have some serious performance implications with large sets.
But for raw performance, repeating the expression is the way to go:
SELECT *
, LEAST(
if (Locate('0',fcccall) >0,Locate('0',fcccall),99),
if (Locate('1',fcccall) >0,Locate('1',fcccall),99),
if (Locate('2',fcccall) >0,Locate('2',fcccall),99),
if (Locate('3',fcccall) >0,Locate('3',fcccall),99),
if (Locate('4',fcccall) >0,Locate('4',fcccall),99),
if (Locate('5',fcccall) >0,Locate('5',fcccall),99),
if (Locate('6',fcccall) >0,Locate('6',fcccall),99),
if (Locate('7',fcccall) >0,Locate('7',fcccall),99),
if (Locate('8',fcccall) >0,Locate('8',fcccall),99),
if (Locate('9',fcccall) >0,Locate('9',fcccall),99)
) AS locationPos
, SUBSTRING(fcccall
, LEAST(
if (Locate('0',fcccall) >0,Locate('0',fcccall),99),
if (Locate('1',fcccall) >0,Locate('1',fcccall),99),
if (Locate('2',fcccall) >0,Locate('2',fcccall),99),
if (Locate('3',fcccall) >0,Locate('3',fcccall),99),
if (Locate('4',fcccall) >0,Locate('4',fcccall),99),
if (Locate('5',fcccall) >0,Locate('5',fcccall),99),
if (Locate('6',fcccall) >0,Locate('6',fcccall),99),
if (Locate('7',fcccall) >0,Locate('7',fcccall),99),
if (Locate('8',fcccall) >0,Locate('8',fcccall),99),
if (Locate('9',fcccall) >0,Locate('9',fcccall),99)
),3
) AS fccsuffix
FROM memberlist
ORDER BY locationPos, fccsuffix
Unfortunately, with MySQL, it's not possible to reference the result of the locationPos column within an expression in the same SELECT list.

For only one numeral I like:
SELECT *
FROM memberlist
ORDER BY SUBSTRING(fcccall,
LOCATE('0',fcccall)+
LOCATE('1',fcccall)+
LOCATE('2',fcccall)+
LOCATE('3',fcccall)+
LOCATE('4',fcccall)+
LOCATE('5',fcccall)+
LOCATE('6',fcccall)+
LOCATE('7',fcccall)+
LOCATE('8',fcccall)+
LOCATE('9',fcccall),3)
But the sensible approach is not to store two separate bits of information in one field.

JOIN on keys that don't have the same value

I am trying to do an INNER JOIN on two tables that have similar values, but not quite the same. One table has a fully qualified host name for its primary key, and the other the hosts short name, as well as the subdomain. It it safe to assume that the short name and the subdomain together are unique.
So I've tried:
SELECT table1.nisinfo.* FROM table1.nisinfo INNER JOIN table2.hosts ON (table1.nisinfo.shortname + '.' + table1.nisinfo.subdomainname + '.domain.com') = table2.hosts.fqhn WHERE table2.hosts.package = 'somepkg';
This doesn't return the results I expect, it returns the first result hundreds of times. I'd like to return distinct rows. It takes a long time to run as well.
What am I doing wrong? I was thinking of running a subquery to get the hostnames, but I don't know what the right path from here is.
Thank you!

You can use group by in your query so you can achieve the desired results you want
please see this two links
Group by with 2 distinct columns in SQL Server
http://www.sqlteam.com/article/how-to-use-group-by-with-distinct-aggregates-and-derived-tables

Try putting your results into a temp table and then view the table to make sure that the columns are as expected.
SELECT table1.nisinfo.*, table1.nisinfo.shortname + '.' + table1.nisinfo.subdomainname + '.domain.com' AS ColID
INTO #temp
FROM table1.nisinfo;
Select *
from #temp INNER JOIN table2.hosts ON ##temp.ColID = table2.hosts.fqhn
WHERE table2.hosts.package = 'somepkg'
;
Put a Group By clause at the end of the second statement

So in this case, I used a subquery to get the initial results, and then used a join.
SELECT table1.nisinfo.* FROM table1.nisinfo JOIN (SELECT distinct(fqhn) FROM table2.hosts WHERE package = 'bash') AS FQ ON ((SUBSTRING_INDEX(FQ.fqhn, '.', 1)) = table1.nisinfo.shortname);

MySQL Select within another select

I have a query as follows
select
Sum(If(departments.vat, If(weeklytransactions.weekendingdate Between
'2011-01-04' And '2099-12-31', weeklytransactions.takings / 1.2,
If(weeklytransactions.weekendingdate Between '2008-11-30' And '2010-01-01',
weeklytransactions.takings / 1.15, weeklytransactions.takings / 1.175)),
weeklytransactions.takings)) As Total,
weeklytransactions.weekendingdate,......
and another that returns a vat rate as follows
select format(Max(Distinct vat_rates.Vat_Rate),3) From vat_rates Where
vat_rates.Vat_From <= '2011-01-03'
I want to replace the hard coded if statement with the lower query, replacing the date in the lower query with weeklytransactions.weekendingdate.
After Kevin's comments, here is the full query I'm trying to get to work;
Select Max(vat_rates.vat_rate) As r,
If(departments.vat, weeklytransactions.takings / r, weeklytransactions.takings) As Total,
weeklytransactions.weekendingdate,
Week(weeklytransactions.weekendingdate),
round(datediff(weekendingdate, (if(month(weekendingdate)>5,concat(year(weekendingdate),'-06-01'),concat(year(weekendingdate)-1,'-06-01'))))/7,0)+1 as fyweek,
cast((Case When Month(weeklytransactions.weekendingdate) >5 Then Concat(Year(weeklytransactions.weekendingdate), '-',Year(weeklytransactions.weekendingdate) + 1) Else Concat(Year(weeklytransactions.weekendingdate) - 1, '-',Year(weeklytransactions.weekendingdate)) End) as char) As fy,
business_units.business_unit
From departments Inner Join (business_units Inner Join weeklytransactions On business_units.buID = weeklytransactions.businessUnit) On departments.deptid = weeklytransactions.departmentId
Where (vat_rates.vat_from <= weeklytransactions.weekendingdate and business_units.Active = true and business_units.sales=1)
Group By weeklytransactions.weekendingdate, business_units.business_unit Order By fy desc, business_unit, fyweek
Regards
Pete

Assuming I read your question correctly, your problem is about having the result of another SELECT used to be returned by the result of your main query (plus depending on how acquainted you are with SQL, maybe you haven't had the occasion to learn about JOINs?).
You can have subqueries you extract data from within a SELECT, provided you define it within the FROMclause. The following query will work, for example:
SELECT A.a, B.b
FROM A
JOIN (SELECT aggregate(c) FROM C) AS B
Notice that there is no reference to table A within the subquery. Thing is, you cannot just add it like that to the query, as the subquery doesn't know it is a subquery. So the following won't work:
SELECT A.a, B.b
FROM A
JOIN (SELECT aggregate(c) FROM C WHERE C.someValue = A.someValue) AS B
Back to basics. What you want to do here visibly, is to aggregate some data associated to each of the records of another table. For that, you will need merge your SELECT queries and use GROUP BY:
SELECT A.a, aggregate(C.c)
FROM A, C
WHERE C.someValue = A.someValue
GROUP BY A.a
Back to your tables, the following should work:
SELECT w.weekendingdate, FORMAT(MAX(v.Vat_Rate, 3)
FROM weeklytransactions AS w, vat_rates AS v
WHERE v.Vat_From <= w.weekendingdate
GROUP BY w.weekendingdate
Feel free to add and remove fields and conditions as you see fit (I wouldn't be surprised that you'd also want to use a lower bound when filtering the records from vat_rates, since the way I have written it above, for a given weekendingdate, you get records from that week + the weeks before!).
So it looks like my first try did not address the actual problem. With the additional information provided in the comments, as well as the new complete query, let's see how this goes.
We are still missing error messages, but normally the query as written should result in MySQL having the following complaint:
ERROR 1109 (42S02): Unknown table 'vat_rates' in field list
Why? Because the vat_rates table does not appear in the FROM clause, whereas it should. Let's make that more obvious by simplifying the query, removing all references to the business_units table as well as the fields, calculations and order that do not add or remove anything to the problem, leaving us with the following:
SELECT MAX(vat_rates.vat_rate) AS r,
IF(d.vat, w.takings / r, w.takings) AS Total
FROM departments AS d
INNER JOIN weeklytransactions AS w ON w.departmentId = d.deptid
WHERE vat_rates.vat_from <= w.weekendingdate
GROUP BY w.weekendingdate
That cannot work, and will produce the error mentioned above. It looks like there is no FOREIGN ID between the weeklytransactions and vat_rates tables, so we have no choice but to do a CROSS JOIN for the moment, hoping that the condition in the WHERE clause and the aggregate function used to get r are enough to fit the business logic at hand here. The following query should return the expected data instead of an error message (I also remove r since that seems to be an intermediate value judging by the comments that were written):
SELECT IF(d.vat, w.takings / MAX(v.vat_rate), w.takings) AS Total
FROM vat_rates AS v, departments AS d
INNER JOIN weeklytransactions AS w ON w.departmentId = d.deptid
WHERE v.vat_from <= w.weekendingdate
GROUP BY w.weekendingdate
From there, assuming it works, you will only need to put back all the parts I removed to get your final query. I am a tad doubtful about the way the VAT rate is gotten here, but I have no idea what your requirements are in that regard so I leave it up to you to make sure that works as expected.

mysql view super slow

this is the query for Unified Medical Language System(UMLS) to find a word related to normalized word. this query result is 165MS, but if I am running VIEW of this same query it is taking 70 sec. I m new to the mysql. Please help me.
Query:
SELECT a.nwd as Normalized_Word,
b.str as String,
c.def as Defination,
d.sty as Semantic_type
FROM mrxnw_eng a, mrconso b, mrdef c, mrsty d
WHERE a.nwd = 'cold'
AND b.sab = 'Msh'
AND a.cui = b.cui
AND a.cui = c.cui
AND a.cui = d.cui
AND a.lui = b.lui
AND b.sui = a.sui
group by a.cui
View definition:
create view nString_Sementic as
SELECT a.nwd as Normalized_Word,
b.str as String,
c.def as Defination,
d.sty as Semantic_type
FROM mrxnw_eng a, mrconso b, mrdef c, mrsty d
WHERE b.sab = 'Msh'
AND a.cui = b.cui
AND a.cui = c.cui
AND a.cui = d.cui
AND a.lui = b.lui
AND b.sui = a.sui
group by a.cui
Selection from view:
select * nString_Sementic
where nwd = 'phobia'

You may be able to get better performance by specifying the VIEW ALGORITHM as MERGE. With MERGE MySQL will combine the view with your outside SELECT's WHERE statement, and then come up with an optimized execution plan.
To do this however you would have to remove the GROUP BY statement from your VIEW. As it is, a temporary table is being created of the entire view first, before being filtered by your WHERE statement.
If the MERGE algorithm cannot be used, a temporary table must be used
instead. MERGE cannot be used if the view contains any of the
following constructs:
Aggregate functions (SUM(), MIN(), MAX(), COUNT(), and so forth)
DISTINCT
GROUP BY
HAVING
LIMIT
UNION or UNION ALL
Subquery in the select list
Refers only to literal values (in this case, there is no underlying
table)
Here is the link with more info. http://dev.mysql.com/doc/refman/8.0/en/view-algorithms.html
If you can change your view to not include the GROUP BY statement, to specify the view's algorithm the syntax is:
CREATE ALGORITHM = MERGE VIEW...
Edit: This answer was originally based on MySQL 5.0. I've updated the links to point to the current documentation, but I have not otherwise confirmed if the answer correct for versions >5.0.

Assuming that mrxnw_eng.nwd is functionally dependent on mrxnw_eng.cui, try changing the group by clause of the view to include a.nwd - like so:
group by a.cui, a.nwd