I am trying to build a Query in MS Access that returns the last date/time for a given entity ID. Research shows that using the MAX() function on the corresponding field and using GROUP BY on the remaining fields appears to be the way to go.
However, this doesn't seem to work in the presence of values that hold 0 hours, 0 minutes and 0 seconds, as it shows those values as well. The query's SQL is as follows:
SELECT Int(Historico_Classificacoes.ID_Entidade) AS ID_Entidade, Max(Historico_Classificacoes.Timestamp_Classificacao) AS [Data da última classificação], Historico_Classificacoes.US_Indicia_Pais_Constituicao, Historico_Classificacoes.US_Indicia_Responsabilidades_Fiscais, Historico_Classificacoes.US_Indicia_Morada_Coletiva, Historico_Classificacoes.US_Indicia_Telefone, Historico_Classificacoes.US_Indicia_Proveniencia_Capital, Historico_Classificacoes.US_Indicia_Beneficiários, Historico_Classificacoes.US_Indicia_Naturalidade, Historico_Classificacoes.US_Indicia_Nacionalidade, Historico_Classificacoes.US_Indicia_Morada_Singular, Historico_Classificacoes.US_Indicia_Laboral
FROM Historico_Classificacoes
GROUP BY Int(Historico_Classificacoes.ID_Entidade), Historico_Classificacoes.US_Indicia_Pais_Constituicao, Historico_Classificacoes.US_Indicia_Responsabilidades_Fiscais, Historico_Classificacoes.US_Indicia_Morada_Coletiva, Historico_Classificacoes.US_Indicia_Telefone, Historico_Classificacoes.US_Indicia_Proveniencia_Capital, Historico_Classificacoes.US_Indicia_Beneficiários, Historico_Classificacoes.US_Indicia_Naturalidade, Historico_Classificacoes.US_Indicia_Nacionalidade, Historico_Classificacoes.US_Indicia_Morada_Singular, Historico_Classificacoes.US_Indicia_Laboral
ORDER BY Int(Historico_Classificacoes.ID_Entidade);
The Historico_Classificacoes table currently holds the following data:
"ID_Entidade";"Timestamp_Classificacao";"Classificacao_DMIF";"Notacao_Risco_BCFT";"US_Indicia_Pais_Constituicao";"US_Indicia_Responsabilidades_Fiscais";"US_Indicia_Morada_Coletiva";"US_Indicia_Telefone";"US_Indicia_Proveniencia_Capital";"US_Indicia_Beneficiários";"US_Indicia_Naturalidade";"US_Indicia_Nacionalidade";"US_Indicia_Morada_Singular";"US_Indicia_Laboral"
"62";20/9/2015 00:00:00;1;30;1;1;1;1;1;1;1;1;1;0
"62";28/9/2015 10:43:38;1;30;1;1;1;1;1;1;1;1;1;1
"62";29/9/2015 17:52:24;1;30;1;1;1;1;1;1;1;1;1;1
"62";29/9/2015 17:52:40;1;30;1;1;1;1;1;1;1;1;1;1
"98";20/9/2015 00:00:00;2;15;1;1;1;1;1;1;0;0;0;0
"98";20/9/2015 00:00:01;0;0;0;0;0;0;0;0;0;0;0;0
The query, when executed in Datasheet View, outputs the following:
"ID_Entidade";"Data da última classificação";"US_Indicia_Pais_Constituicao";"US_Indicia_Responsabilidades_Fiscais";"US_Indicia_Morada_Coletiva";"US_Indicia_Telefone";"US_Indicia_Proveniencia_Capital";"US_Indicia_Beneficiários";"US_Indicia_Naturalidade";"US_Indicia_Nacionalidade";"US_Indicia_Morada_Singular";"US_Indicia_Laboral"
62;29/9/2015 17:52:40;1;1;1;1;1;1;1;1;1;1
62;20/9/2015 00:00:00;1;1;1;1;1;1;1;1;1;0
98;20/9/2015 00:00:00;1;1;1;1;1;1;0;0;0;0
98;20/9/2015 00:00:01;0;0;0;0;0;0;0;0;0;0
There are duplicated records for entities 62 and 98, when only one record for each was expected. Am I missing something here? Why are the entries whose values hold 00:00:00 present?
You may want to consider using an additional query as an intermediate step that identifies the MAX Date/Time combination for each group ID first, then a follow up query that pulls the entire record where that Group ID, Date and Time match, this will ensure you won't have to use First or Min on the rest of your fields, and you will always get the correct data
You use Group By for the last fields like US_Indicia_Morada_Singular and US_Indicia_Laboral. You'll have to use First, Last, Min, or Max on these as well.
Here is your attempt (without the repeated alias)
SELECT INT(ID_Entidade) AS ID_Entidade
, MAX(Timestamp_Classificacao) AS [Data da última classificação]
, US_Indicia_Pais_Constituicao
, US_Indicia_Responsabilidades_Fiscais
, US_Indicia_Morada_Coletiva
, US_Indicia_Telefone
, US_Indicia_Proveniencia_Capital
, US_Indicia_Beneficiários
, US_Indicia_Naturalidade
, US_Indicia_Nacionalidade
, US_Indicia_Morada_Singular
, US_Indicia_Laboral
FROM Historico_Classificacoes
GROUP BY INT(ID_Entidade)
, US_Indicia_Pais_Constituicao
, US_Indicia_Responsabilidades_Fiscais
, US_Indicia_Morada_Coletiva
, US_Indicia_Telefone
, US_Indicia_Proveniencia_Capital
, US_Indicia_Beneficiários
, US_Indicia_Naturalidade
, US_Indicia_Nacionalidade
, US_Indicia_Morada_Singular
, US_Indicia_Laboral
ORDER BY INT(ID_Entidade);
From you comments, here is SQL that is close to what you need. I have added the field "AnotherField" for you as you may or may not need to add field here.
This currently selects the whole record from the table, but only the single "most recent" record for each value found in the AnotherField is listed.
It may be that you need more that one field where AnotherField appears in the SQL. Think of the field you use instead of AnotherField as being the fields that need to be used to find the maximum date record.
SELECT Main.*
FROM Historico_Classificacoes AS Main
INNER JOIN ( SELECT AnotherField
, MAX(Timestamp_Classificacao) AS [MaxDate]
FROM Historico_Classificacoes
GROUP BY AnotherField
)
AS MostRecent
ON ( Main.AnotherField = MostRecent.AnotherField
AND
Main.Timestamp_Classificacao = MostRecent.MaxDate
)
Related
I need to merge some randomly uppercased data that has been collected in an SQLite table key_val, such that key is always lowercase and no vals are lost. There is a unique compound index on key,val.
The initial data looks like this:
key|val
abc|1
abc|5
aBc|1
aBc|5
aBc|3
aBc|2
AbC|1
abC|3
The result after the merge would be
key|val
abc|1
abc|2
abc|3
abc|5
In my programmer brain, I would
for each `key` with upper case letters;
if a lower cased `key` is found with the same value
then delete `key`
else update `key` to lower case
Re implementing the loop has a sub query for each row found with upper case letters, to check if the val already exists as a lower case key
If it does, I can delete the cased key.
From there I can UPDATE key = lower(key) as the "duplicates" have been removed.
The first cut of the programming method of finding the dupes is:
SELECT * FROM key_val as parent
WHERE parent.key != lower(parent.key)
AND 0 < (
SELECT count(s.val) FROM key_val as s
WHERE s.key = lower(parent.key) AND s.val = parent.val
)
ORDER BY parent.key DESC;
I'm assuming there's a better way to do this in SQLite? The ON CONFLICT functionality seems to me like it should be able to handle the dupe deletion on UPDATE but I'm not seeing it.
First delete all the duplicates:
DELETE FROM key_val AS k1
WHERE EXISTS (
SELECT 1
FROM key_val AS k2
WHERE LOWER(k2.key) = LOWER(k1.key) AND k2.val = k1.val AND k2.rowid < k1.rowid
);
by keeping only 1 combination of key and val with the min rowid.
It is not important if you kept the key with all lower chars or not, because the 2nd step is to update the table:
UPDATE key_val
SET key = LOWER(key);
See the demo.
Honestly it might just be easier to create a new table and then insert into it. As it seems you really just want a distinct select here, use:
INSERT INTO kev_val_new ("key", val)
SELECT DISTINCT LOWER("key"), val
FROM key_val;
Once you have populated the new table, you may drop the old one, and then rename the new one to the previous name:
DROP TABLE key_val;
ALTER TABLE key_val_new RENAME TO key_val;
I agree with #Tim that it would be easire to re-create table using simple select distict lower().. statement, but that's not always easy if table has dependant objects (indexes, triggers, views). In this case this can be done as sequence of two steps:
insert lowered keys which are not still there:
insert into t
select distinct lower(tr.key) as key, tr.val
from t as tr
left join t as ts on ts.key = lower(tr.key) and ts.val = tr.val
where ts.key is null;
now when we have all lowered keys - remove other keys:
delete from t where key <> lower(key);
See fiddle: http://sqlfiddle.com/#!5/84db50/11
However this method assumes that key is always populated (otherwise it would be a strange key)
If vals can be null then "ts.val = tr.val" should be replaced with more complex stuff like ifnull(ts.val, -1) = ifnull(tr.val, -1) where -1 is some unused value (can be different). If we can't assume any unused value like -1 then it should be more complex check for null / not null cases.
I'd like to be able to do the following initially and also at anytime.
insert into balance (closing_amount, opening_amount, created, tx_id)
select closing_amount + :value, closing_amount, :date, :tx_id from balance order by id desc limit 1
Basically I'm inserting by using previous values. But if there are no values to begin with, nothing gets inserted.
I could use a union to which works the first time but duplicates on subsequent inserts.
I want to avoid two trips. Is there a way to do this?
Also, the tx_id will always be unique.
I think you want something like this:
insert into balance (closing_amount, opening_amount, created, tx_id)
select coalesce(max(closing_amount), 0) + :value,
coalesce(max(closing_amount), 0),
:date,
:tx_id
from (
select closing_amount
from balance
order by tx_id desc
limit 1
) t;
You only need the last closing_amount, so max(closing_amount) from the subquery, which returns 1 row or none at all, will return that closing_amount or null respectively.
See a simplified demo.
I'm sorry for the confusing title, but couldn't find another way to ask it.
Let's say I want to write a procedure add_salesline. I enter all the fields with parameters, except subtotal. Subtotal (just the price for the salesline) needs to be calculated based on fields in other tables such as productprice in the table products, pricereduction in the table promotion, etc. (based on the properties).
How can I do this? I've been trying to solve this problem for a good week now, and it's just not working...
Presumably one of the parameters passed to procedure add_salesline() is productid, or whatever. So you use that to SELECT products.productprice, promotion.pricereduction and whatever else you need to perform the calculation.
The purpose of writing a stored procedure is to associate several calls into a single program unit. So add_salesline() might look something like this (lots of caveats because your question is very light on details):
create or replace procedure add_salesline(
p_orderno in salesline.orderno%type
, p_salesqty in salesline.salesqty%type
, p_productid in products.productid%type
)
is
new_rec salesline%rowtype;
begin
new_rec.orderno := p_orderno;
new_rec.salesqty := p_salesqty;
new_rec.productid := p_productid;
select p_salesqty * (p.productprice * nvl(pp.pricereduction, 1))
into new_rec.subtotal
from products p
left outer join promotion pp
on pp.productid = p.productid
where p.productid = p_productid
;
insert into salesline
value new_rec;
end;
This code assumes pricereduction is a rate. If the value is an absolute discount the formula will be different (p.productprice - nvl(pp.pricereduction, 0)). Or if it's a replacement price: coalesce(pp.pricereduction, p.productprice).
I have a reservation table which the user will insert records into.
The User does not select the car just the type.
Once the record is inserted I want some triggers to do the following:-
The date and vehicle combination to a log file the data and vehicle are UNIQUE(date,car) so the same reservation cannot be made twice therefore a car cannot be double booked.
SO my issue is how do I now get the trigger to select the next available car of that type?
I can get it to select the next car by just saying Car.carid != Log.carid but that is not using the date as a second check so I could not then use the vehicle on another date.
Simply putting AND between the check doesnt work meaning
WHERE Car.carid != Log.carid AND Reservation.date != C.datewhen
Some guidance would be much appreciated!
I think this query is what you are after...
SELECT MIN(c.carid)
FROM all_cars c
WHERE c.type = 'CAR TYPE'
AND NOT EXISTS
(SELECT 1
FROM reservation r
WHERE r.date = 'THE DATE'
AND r.carid = c.carid)
If the query returns a NULL value then no cars are available.
Or you could take off the MIN and just use the first record returned.
I have a MySQL table Page with 2 columns: PageID and OrderByMethod.
I also then have a Data table with lots of columns including PageID (the Page the data is on), DataName, and DataDate.
I want OrderByMethod to have one of three entries: Most Recent Data First, Most Recent Data Last, and Alphabetically.
Is there a way for me to tack an "ORDER BY" clause to the end of this query that will vary its ordering method based on the contents of the "OrderByMethod" column? For example, in this query, I would want to have the ORDER BY clause contain whatever ordering rule is stored in Page 1's OrderByMethod column.
GET * FROM `Data` WHERE `Data`.`PageID`=1 ORDER BY xxxxxx;
Maybe a SELECT clause in the ORDER BY clause? I'm not sure how that would work though.
Thanks!
select Data.*
from Data
inner join Page on (Data.PageID=Page.PageID)
where Data.PageID=1
order by
if(Page.OrderByMethod='Most Recent Data First', now()-DataDate,
if(Page.OrderByMethod='Most Recent Data Last', DataDate-now(), DataName)
);
You can probably do this with the IF syntax to generate a column that you can then order by.
SELECT *, IF(Page.OrderBy = 'Alphabetically', Data.DataName, IF(Page.OrderBy = 'Most Recent Data First', NOW() - Data.DataDate, Data.DataDate - NOW())) AS OrderColumn
FROM Data
INNER JOIN Page ON Data.PageID = Page.PageID
WHERE Page.PageID = 1
ORDER BY OrderColumn
The direction of the ordering is determined in the calculation of the data instead of specifying a direction in the ORDER BY
Can you just append the order by clause to the select statement and rebind the table on postback?
If you want to use the content of the column in Page table as an expression in ORDER BY you have to do it using prepared statements. Let say, you store in OrderByMethod something like "field1 DESC, field2 ASC" and you want this string to be used as it is:
SET #order_by =(SELECT OrderByMethod FROM Page WHERE id = [value]);
SET #qr = CONCAT(your original query,' ORDER BY ', #order_by);
PREPARE stmt FROM #qr;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;
If you want the result set to be sorted based on the value of OrderByMethod , you can use IF as it was already mentioned by others, or CASE :
...
ORDER BY
CASE OrderByMethod
WHEN 'val1' THEN field_name1
WHEN 'val2' THEN field_name2
....etc
END