I got two statements and I want to calculate their values. Both values have to be calculated 5 - 5 = ( I want to see the answer 0 )
SELECT COUNT(*) AS 'Aantal stoelen geboekt'
FROM Boekingsregel, Vlucht
WHERE Boekingsregel.Vlucht_Vlucht_Id = Vlucht.Vlucht_Id
AND Vlucht_Datum = '2017-04-10';
SELECT min(Vliegtuig_Aantal_Stoelen) AS 'Max aantal stoelen'
FROM Vliegtuig;
While I do not see any relation of the two queries you also should not use an alias with spaces. Make your alias as short as possible but can define what value it holds, but since this is your query you know better than I do.
As for your problem you can combine the two queries into one something like this:
SELECT BR.`Aantal stoelen geboekt` - VT.`Max aantal stoelen` AS TheResult
FROM (SELECT COUNT(*) AS `Aantal stoelen geboekt`
FROM Boekingsregel, Vlucht
WHERE Boekingsregel.Vlucht_Vlucht_Id = Vlucht.Vlucht_Id
AND Vlucht_Datum = '2017-04-10') BR,
(SELECT min(Vliegtuig_Aantal_Stoelen) AS `Max aantal stoelen` FROM Vliegtuig) VT;
NOTE: Not tested I just type it here.
If this is not what you are looking for then maybe you should explain your requirements in greater detail so dhat everyone can understand and will be able to help you.
First, learn to use proper JOIN syntax.
Second, combine these in the FROM clause.
SELECT COUNT(*) AS AantalStoelenGeboekt, vt.MaxAantalStoelen
FROM Boekingsregel b JOIN
Vlucht v
ON b.Vlucht_Vlucht_Id = v.Vlucht_Id CROSS JOIN
(SELECT min(Vliegtuig_Aantal_Stoelen) AS MaxAantalStoelen
FROM Vliegtuig
) vt
WHERE v.Vlucht_Datum = '2017-04-10';
Note: MySQL allows this syntax. Perhaps a cleaner way is to use an aggregation function on MaxAantalStoelen:
SELECT COUNT(*) AS AantalStoelenGeboekt,
MAX(vt.MaxAantalStoelen) as MaxAantalStoelen
FROM Boekingsregel b JOIN
Vlucht v
ON b.Vlucht_Vlucht_Id = v.Vlucht_Id CROSS JOIN
(SELECT min(Vliegtuig_Aantal_Stoelen) AS MaxAantalStoelen
FROM Vliegtuig
) vt
WHERE v.Vlucht_Datum = '2017-04-10';
Related
I have a SQL query that links 2 tables to provide the data if a horse is in both the tables:
SELECT ProformSystem.TheDate as racedate,
ProformSystem.Course as course,
ProformSystem.TheTime as thetime,
ProformSystem.Horse as horse,
ATRSpeedRatings.rank as rank
FROM ATRSpeedRatings
INNER JOIN ProformSystem ON (ATRSpeedRatings.Horse = trim(ProformSystem.Horse)) AND (ATRSpeedRatings.TheDate = ProformSystem.TheDate) order by ProformSystem.TheTime;"
Is it possible that if the horse in ProformSystem.Horse is NOT in ATRSpeedRatings.Horse then I just make rank = 0 as a default value, or would I need to run a separate query?
This way I can display all horses from ProformSystem even if they don't have a rank in ATRSpeedRatings.
I think you want a left join and coalesce():
SELECT ps.TheDate as racedate, ps.Course as course, ps.TheTime as thetime,
ps.Horse as horse, COALESCE(sr.rank, 0) as rank
FROM ProformSystem ps LEFT JOIN
ATRSpeedRatings sr
ON sr.Horse = TRIM(ps.Horse) AND sr.TheDate = ps.TheDate)
ORDER BY ps.TheTime;
Note that this query uses table aliases. These make the query easier to write and to read.
Also, the JOIN condition sr.Horse = trim(ps.Horse) is highly suspect. You should fix the data so there are no spaces in ProformSystem. Fixing the data is more efficient and it will prevent problems on future queries.
I have a table with exchange rate like below
And I am using the maxofdate to pick all these values based on currency code. But the query is giving blank.
Select USDAMOUNT * dbo.EXCHANGERATEAMT
from dbo.Amount_monthly
Left Join dbo.EXCHANGERATE on dbo.Amount_monthly.Currencycode=dbo.EXCHANGERATE.fromcurrencycode
WHERE ValidToDateTime = (Select MAX(ValidToDateTime) from dbo.EXCHANGERATE)
AND dbo.EXCHANGERATE.EXCHANGERATETYPECODE = 'DAY'
Using this statement
CONVERT(DATE,ValidToDateTime) = CONVERT(DATE,GETDATE()-1)
instead of subquery is giving me expected result.
Can someone correct this.
thanks in advance.
If I understand correctly, you need two things. First, the condition for the max() needs to match the condition in the outer query. Second, if you really want a left join, then conditions on the second table need to go in the on clause.
The resulting query looks like:
Select . . .
from dbo.Amount_monthly am Left Join
dbo.EXCHANGERATE er
on am.Currencycode = er.fromcurrencycode and
er.ValidToDateTime = (Select max(er2.ValidToDateTime)
from dbo.EXCHANGERATE er2
where er2.EXCHANGERATETYPECODE = 'DAY'
) and
er.EXCHANGERATETYPECODE = 'DAY';
I would write this using window functions, but that is a separate issue.
Try removing WHERE clause for ValidToDateTime and include it in the JOIN as AND condition
SELECT USDAMOUNT * dbo.EXCHANGERATEAMT
FROM dbo.Amount_monthly
LEFT JOIN dbo.EXCHANGERATE
ON dbo.Amount_monthly.Currencycode = dbo.EXCHANGERATE.fromcurrencycode
AND ValidToDateTime = (SELECT MAX(ValidToDateTime) --remove WHERE clause
FROM dbo.EXCHANGERATE)
AND dbo.EXCHANGERATE.EXCHANGERATETYPECODE = 'DAY';
I cleaned up your query a bit: as the other folks mentioned you needed to close the parentheses around the MAX(Date) sub-query, and if you reference a LEFT JOINed table in the WHERE clause, it behaves like an INNER JOIN, so I changed to in INNER. You also had "dbo" sprinkled in as a field prefix, but that (the namespace) only prefixes a database, not a field. I added the IS NOT NULL check just to avoid SQL giving the "null values were eliminated" SQL warning. I used the aliases "am" for the first table and "er" for the 2nd, which makes it more readable:
SELECT am.USDAMOUNT * er.EXCHANGERATEAMT
FROM dbo.Amount_monthly am
JOIN dbo.EXCHANGERATE er
ON am.Currencycode = er.fromcurrencycode
WHERE er.ValidToDateTime = (SELECT MAX(ValidToDateTime) FROM dbo.EXCHANGERATE WHERE ValidToDateTime IS NOT NULL)
AND er.EXCHANGERATETYPECODE = 'DAY'
If you're paranoid like I am, you might also want to make sure the exchange rate is not zero to avoid a divide-by-zero error.
Really trying to figure out, why SQL query doesnt go through. I assume the structure is a bit wrong, but cant figure out where exactly. The references to tables are all correct.
SELECT tap_questionnaires.id,
tap_questionnaires.NAME,
tap_questionnaires.active,
tap_useranswers_ip.questionnaire_id,
Count(tap_useranswers_ip.ip)
FROM tap_questionnaires
LEFT JOIN tap_useranswers_ip
ON tap_questionnaires.id = tap_useranswers_ip.questionnaire_id
WHERE author_email = admin#admin.com
If you use count you need to use group by for the other columns in your select clause.
SELECT TAP_questionnaires.id, TAP_questionnaires.name, TAP_questionnaires.active, TAP_useranswers_ip.questionnaire_id, COUNT(TAP_useranswers_ip.ip) FROM TAP_questionnaires LEFT JOIN TAP_useranswers_ip on TAP_questionnaires.id=TAP_useranswers_ip.questionnaire_id WHERE author_email="admin#admin.com"
group by TAP_questionnaires.id, TAP_questionnaires.active
I think TAP_questionnaires.name it's not necessary because I suppose it depends on TAP_questionnaires.id. TAP_useranswers_ip.questionnaire_id is the same value as TAP_questionnaires.id
Hope that helps!
I think this version is clearer:
SELECT q.id, q.name, q.active, COUNT(a.ip)
FROM TAP_questionnaires q LEFT JOIN
TAP_useranswers_ip a
ON on q.id = a.questionnaire_id
WHERE author_email = 'admin#admin.com'
GROUP BY q.id, q.name, q.active;
Notes:
You need a GROUP BY.
You need single quotes around the string constant.
Table aliases make the query easier to write and to read.
There is no reason to include a.questionnaire_id. You already have q.id.
I am able to keep a running total with the below query, and it does that just fine. What I really want, is when the gap field is greater than or equal to the date_diff field, the running total should reset back to the current hrly_qty. I'm sure I could achieve my results with a cursor, but I wanted to know of possible other ways. Ideas?
Example:
WITH CTE AS
(
SELECT a.*, SUM(b.hrly_qty) AS running_total, c.gap
FROM #tmpTrxhist2 a
INNER JOIN #tmpTrxhist2 b ON a.people_id = b.people_id
AND b.sequence_id <= a.sequence_id
INNER JOIN incent_level c ON a.owner_division_id = c.owner_division_id
GROUP BY a.date_diff, a.owner_division_id, a.people_id, a.sequence_id,
a.hrly_qty, c.gap
)
SELECT * FROM CTE
ORDER BY people_id, sequence_id
You seldom need a cursor! A simple case statement should suffice. Of the top of my head something like:
WITH CTE AS
(
SELECT a.*, SUM(b.hrly_qty) AS running_total, c.gap
FROM #tmpTrxhist2 a
INNER JOIN #tmpTrxhist2 b ON a.people_id = b.people_id
AND b.sequence_id <= a.sequence_id
INNER JOIN incent_level c ON a.owner_division_id = c.owner_division_id
GROUP BY a.date_diff, a.owner_division_id, a.people_id, a.sequence_id,
a.hrly_qty, c.gap
)
SELECT *,
CASE
WHEN gap >= date_diff then hrly_qty else gap
END as comp_gap
FROM CTE
ORDER BY people_id, sequence_id
Run the execution plans between the two but SQL is almost always much happier trying to optimise non-cursored code. In my field at least, you usually find cursors are over used and abused by 'proper' C/C++ programmers because they get in their comfort zone when see something that looks a bit like a while-loop rather than think about sets of data. There is a place for cursors, but this isn't it!
So, this query is currently used in a webshop to retrieve technical data about articles.
It has served its purpose fine except the amount of products shown have increased lately resulting in unacceptable long loading times for some categories.
For one of the worst pages this (and some other queries) get requested about 80 times.
I only recently learned that MySQL does not optimize sub-queries that don't have a depending parameter to only run once.
So if someone could help me with one of the queries and explain how you can replace the in's and exists's to joins, i will probably be able to change the other ones myself.
select distinct criteria.cri_id, des_texts.tex_text, article_criteria.acr_value, article_criteria.acr_kv_des_id
from article_criteria, designations, des_texts, criteria, articles
where article_criteria.acr_cri_id = criteria.cri_id
and article_criteria.acr_art_id = articles.art_id
and articles.art_deliverystatus = 1
and criteria.cri_des_id = designations.des_id
and designations.des_lng_id = 9
and designations.des_tex_id = des_texts.tex_id
and criteria.cri_id = 328
and article_criteria.acr_art_id IN (Select distinct link_art.la_art_id
from link_art, link_la_typ
where link_art.la_id = link_la_typ.lat_la_id
and link_la_typ.lat_typ_id = 17484
and link_art.la_ga_id IN (Select distinct link_ga_str.lgs_ga_id
from link_ga_str, search_tree
where link_ga_str.lgs_str_id = search_tree.str_id
and search_tree.str_type = 1
and search_tree.str_id = 10132
and EXISTS (Select *
from link_la_typ
where link_la_typ.lat_typ_id = 17484
and link_ga_str.lgs_ga_id = link_la_typ.lat_ga_id)))
order by article_criteria.acr_value
I think this one is the main badguy with sub-sub-sub-queries
I just noticed i can remove the last exist and still get the same results but with no increase in speed, not part of the question though ;) i'll figure out myself whether i still need that part.
Any help or pointers are appreciated, if i left out some useful information tell me as well.
I think this is equivalent:
SELECT DISTINCT c.cri_id, dt.tex_text, ac.acr_value, ac.acr_kv_des_id
FROM article_criteria AS ac
JOIN criteria AS c ON ac.acr_cri_id = c.cri_id
JOIN articles AS a ON ac.acr_art_id = a.art_id
JOIN designations AS d ON c.cri_des_id = d.des_id
JOIN des_texts AS dt ON dt.tex_id = d.des_tex_id
JOIN (SELECT distinct la.la_art_id
FROM link_art AS la
JOIN link_la_typ AS llt ON la.la_id = llt.lat_la_id
JOIN (SELECT DISTINCT lgs.lgs_ga_id
FROM link_ga_str AS lgs
JOIN search_tree AS st ON lgs.lgs_str_id = st.str_id
JOIN link_la_typ AS llt ON lgs.lgs_ga_id = llt.lat_ga_id
WHERE st.str_type = 1
AND st.str_id = 10132
AND llt.lat_typ_id = 17484) AS lgs
ON la.la_ga_id = lgs.lgs_ga_id
WHERE llt.lat_typ_id = 17484) AS la
ON ac.acr_art_id = la.la_art_id
WHERE a.art_deliverystatus = 1
AND d.des_lng_id = 9
AND c.cri_id = 328
ORDER BY ac.acr_value
All the IN <subquery> clauses can be replaced with JOIN <subquery>, where you then JOIN on the column being tested equaling the column returned by the subquery. And the EXISTS test is converted to a join with the table, moving the comparison in the subquery's WHERE clause into the ON clause of the JOIN.
It's probably possible to flatten the whole thing, instead of joining with subqueries. But I suspect performance will be poor, because this won't reduce the temporary tables using DISTINCT. So you'll get combinatorial explosion in the resulting cross product, which will then have to be reduced at the end with the DISTINCT at the top.
I've converted all the implicit joins to ANSI JOIN clauses, to make the structure clearer, and added table aliases to make things more readable.
In general, you can convert a FROM tab1 WHERE ... val IN (SELECT blah) to a join like this.
FROM tab1
JOIN (
SELECT tab1_id
FROM tab2
JOIN tab3 ON whatever = whatever
WHERE whatever
) AS sub1 ON tab1.id = sub1.tab1_id
The JOIN (an inner join) will drop the rows that don't match the ON condition from your query.
If your tab1_id values can come up duplicate from your inner query, use SELECT DISTINCT. But don't use SELECT DISTINCT unless you need to; it is costly to evaluate.