I'd want a query to fetch all columns of a tuple according to a column's lowest value in the table:
SELECT *, MIN(Opened) FROM Account
And for some reason this throws an error:
ORA-00923: FROM keyword not found where expected
This is basic stuff in my opinion, coming from SQLite, but Oracle is new to me.
I created a table like:
CREATE TABLE Account (
Act_id INTEGER,
Opened DATE,
Balance NUMBER(10,2),
CONSTRAINT act_pk PRIMARY KEY(act_id)
)
If I enter any other column name (e.g. SELECT balance, MIN(opened)), it gives another error:
ORA-00937: not a single-group group function
According to this tutorial at least the * notation is in Oracle. And the MIN works by itself. Am I missing something?
SQLite is "broken" with respect to the syntax that you learned. It is the only database that returns the entire row of the minimum or maximum in such a case. There are simple ways to do this, so I'm not sure why the designers felt the need to include that particular (mis)feature.
Just use order by and rownum if you want one row:
select a.*
from (select a.*
from account a
order by opened asc
) a
where rownum = 1;
If you want all rows with the minimum value, use a subquery:
select a.*
from account a
where a.opened = (select min(a2.opened) from account a2);
When you're asking for BALANCE and MIN(OPENED) you need to specify a GROUP BY, as in
SELECT BALANCE, MIN(OPENED)
FROM ACCOUNT
GROUP BY BALANCE
Earlier you said "I'd want a query to fetch all columns of a tuple according to a column's lowest value in the table". My interpretation of this is that you need a WHERE clause:
SELECT *
FROM ACCOUNT
WHERE OPENED = (SELECT MIN(OPENED) FROM BALANCE)
Or perhaps you meant you wanted all the columns from ACCOUNT, along with the min value of OPENED for the entire table. In that case I'd suggest a CROSS JOIN
SELECT *
FROM ACCOUNT
CROSS JOIN (SELECT MIN(OPENED) AS MIN_OPENED FROM ACCOUNT)
Best of luck.
Related
Given a schema and data in SQLite 3.7.17 (I'm stuck with this version):
CREATE TABLE reservations (id INTEGER NOT NULL PRIMARY KEY,NodeID INTEGER,ifIndex INTEGER,dt TEXT,action TEXT,user TEXT,p TEXT);
INSERT INTO "reservations" VALUES(1,584,436211200,'2022-03-12 10:10:00','R','s','x');
INSERT INTO "reservations" VALUES(2,584,436211200,'2022-03-12 10:10:01','R','s','x');
INSERT INTO "reservations" VALUES(3,584,436211200,'2022-03-12 10:10:05','U','s','x');
INSERT INTO "reservations" VALUES(4,584,436211200,'2022-03-12 10:09:01','R','s','x');
I'm trying to get the most recent action for each pair of (NodeID,ifIndex).
Running SELECT MAX(dt),action FROM reservations GROUP BY NodeId,ifIndex; I get:
MAX(dt)|action
2022-03-12 10:10:05|U
Perfect.
Now I want to select just the action from this query (dropping the MAX(dt)): SELECT t.action FROM (SELECT MAX(dt),action FROM reservations GROUP BY NodeId,ifIndex) AS t;:
t.action
R
This I don't understand. Also: SELECT t.* FROM (SELECT MAX(dt),action FROM reservations GROUP BY NodeId,ifIndex) AS t;:
MAX(dt)|action
2022-03-12 10:10:05|U
gives the correct value. So why does the query not seem to be querying against the subquery?
Perhaps it's a bug in this version of SQLite as SQLFiddle works fine (http://sqlfiddle.com/#!7/f7619a/4)
In attempt to workaround this issue I use this query: SELECT t2.action FROM (SELECT MAX(dt),* FROM reservations GROUP BY NodeId,ifIndex) AS t1 INNER JOIN reservations AS t2 on t1.id = t2.i which seems to work:
action
U
You are right, this seems to be a bug in your SQLite version.
To get into more detail, you are using SQLite's GROUP BY extension "Bare columns in an aggregate query".
In standard SQL and almost all RDBMS your query
SELECT MAX(dt), action FROM reservations GROUP BY NodeId, ifIndex;
is invalid. Why is that? You group by NodeId and ifIndex, thus aggregating your data down to one result row per NodeId and ifIndex. In each such row you want to show the group's maximum date and the group's action. But while there is one maximum date for a group, there is no one action for it, but several. Your query is considered invalid in standard SQL, because you don't tell the DBMS which of the group's actions you want to see. This could be the minimum action for example (i.e. the first in alphabetical order). That means there must be an aggregation function invoked on that column.
Not so in SQLite. When SQLite finds a "bare column" in a GROUP BY query that is meant to find a MAX or MIN of a column, it considers this to mean to take the bare column's value from the row where the minimum or maximum is found in. This is an extension to the SQL standard, and SQLite is the only DBMS I know of to feature this. You can read about this in the SQLite docs: Search "Bare columns in an aggregate query" in https://www.sqlite.org/lang_select.html#resultset.
SELECT MAX(dt), action FROM reservations GROUP BY NodeId, ifIndex;
hence finds the action in the row with the maximum dt. If you selected MIN(dt) instead, it would get you the action of the row with the minimum dt.
And of course a query selecting from a subquery result should still get the same value. It seems, however, that in your version SQLite gets confused with its bare column detection. It doesn't throw an error telling you it doesn't know which action to select, but it doesn't select the maximum dt's action either. Obviously a bug.
In standard SQL (and almost any RDBMS) your original query would be written like this:
SELECT dt, action
FROM reservations r
WHERE dt =
(
SELECT MAX(dt)
FROM reservations mr
WHERE mr.NodeId = r.NodeId AND mr.ifIndex = r.ifIndex
);
or like this:
SELECT dt, action
FROM reservations r
WHERE NOT EXISTS
(
SELECT NULL
FROM reservations gr
WHERE gr.NodeId = r.NodeId
AND gr.ifIndex = r.ifIndex
AND gr.dt > r.dt
);
or like this:
SELECT dt, action
FROM
(
SELECT dt, action, MAX(dt) OVER (PARTITION BY NodeId, ifIndex) AS max_dt
FROM reservations
) with_max_dt
WHERE dt = max_dt;
And there are still other ways to get the top row(s) per group.
In any of these proper SQL queries, you can remove dt from the select list and still get the maximum dt's action.
I have two queries that I'm running separately from a PHP script. The first is checking if an identifier (group) has a timestamp in a table.
SELECT
group, MAX(timestamp) AS timestamp, value
FROM table_schema.sample_table
GROUP BY group, value
If there is no timestamp, then it runs this second query that retrieves the minimum timestamp from a separate table:
SELECT
group, MIN(timestamp) as timestamp, value AS value
FROM table_schema.src_table
GROUP BY group, value
And goes on from there.
What I would like to do, for the sake of conciseness, is to have a single query that runs the first statement, but that defaults to the second if NULL. I've tried with coalesce() and CASE statements, but they require subqueries to return single columns (which I hadn't run into being an issue yet). I then decided I should try a JOIN on the table with the aggregate timestamp to get the whole row, but then quickly realized I can't variate the table being joined (not to my knowledge). I opted to try joining both results and getting the max, something like this:
Edit: I am so tired, this should be a UNION, not a JOIN
sorry for any possible confusion :(
SELECT smpl.group, smpl.value, MAX(smpl.timestamp) AS timestamp
FROM table_schema.sample_table as smpl
INNER JOIN
(SELECT src.group, src.value, MIN(src.timestamp) AS timestamp
FROM source_table src
GROUP BY src.group, src.value) AS history
ON
smpl.group = history.group
GROUP BY smpl.group, smpl.value
I don't have a SELECT MAX() on this because it's really slow as is, most likely because my SQL is a bit rusty.
If anyone knows a better approach, I'd appreciate it!
Please try this:
select mx.group,(case when mx.timestamp is null then mn.timestamp else mx.timestamp end)timestamp,
(case when mx.timestamp is null then mn.value else mx.value end)value
(
SELECT
group, MAX(timestamp) AS timestamp, value
FROM table_schema.sample_table
GROUP BY group, value
)mx
left join
(
SELECT
group, MIN(timestamp) as timestamp, value AS value
FROM table_schema.src_table
GROUP BY group, value
)mn
on mx.group = mn.group
I want to list out the product which has highest sales amount on date wise.
note: highest sales amount in the sense max(sum(sales_amnt)...
by using if or case In the procedure in sap hana SQL....
I did this by using with the clause :
/--------------------------CORRECT ONE ----------------------------------------------/
WITH ranked AS
(
SELECT Dense_RAnk() OVER (ORDER BY SUM("SALES_AMNT"), "SALES_DATE", "PROD_NAME") as rank,
SUM("SALES_AMNT") AS Amount, "PROD_NAME",count(*), "SALES_DATE" FROM "KABIL"."DATE"
GROUP BY "SALES_DATE", "PROD_NAME"
)
SELECT "SALES_DATE", "PROD_NAME",Amount
FROM ranked
WHERE rank IN ( select MAX(rank) from ranked group by "SALES_DATE")
ORDER BY "SALES_DATE" DESC;
this is my table
You can not use IF along with SELECT statement. Note that, you can achieve most of boolean logics with CASE statement syntax
In select, you are applying it over a column and your logic will be executed as many as times the count of result set rows. Hence , righting an imperative logic is not well appreciated. Still, if you want to do the same, create a calculation view and use intermediate calculated columns to achieve what you are expecting .
try this... i got an answer ...
select "SALES_DATE","PROD_NAME",sum("SALES_AMNT")
from "KABIL"."DATE"
group by "SALES_DATE","PROD_NAME"
having (SUM("SALES_AMNT"),"SALES_DATE") IN (select
MAX(SUM_SALES),"SALES_DATE"
from (select SUM("SALES_AMNT")
as
SUM_SALES,"SALES_DATE","PROD_NAME"
from "KABIL"."DATE"
group by "SALES_DATE","PROD_NAME"
)
group by "SALES_DATE");
I have read many answers here, but until now nothing could help me. I'm developing a ticket system, where each ticket has many updates.
I have about 2 tables: tb_ticket and tb_updates.
I created a SELECT with subqueries, where it took a long time (about 25 seconds) to get about 1000 rows. Now I changed it to INNER JOIN instead many SELECTs in subqueries, it is really fast (70 ms), but now I get duplicates tickets. I would like to know how can I do to get only the last row (ordering by time).
My current result is:
...
67355;69759;"COMPANY X";"2014-08-22 09:40:21";"OPEN";"John";1
67355;69771;"COMPANY X";"2014-08-26 10:40:21";"UPDATE";"John";1
The first column is the ticket ID, the second is the update ID... I would like to get only a row per ticket ID, but DISTINCT does not work in this case. Which row should be? Always the latest one, so in this case 2014-08-26 10:40:21.
UPDATE:
It is a postgresql database. I did not share my current query because it has only portuguese names, so I think it would not help at all.
SOLUTION:
Used_By_Already had the best solution to my problem.
Without the details of your tables one has to guess the field names, but it seems that tb_updates has many records for a single record in tb_ticket (a many to one relationship).
A generic solution to your problem - to get just the "latest" record - is to use a subquery on tb_updates (see alias mx below) and then join that back to tb_updates so that only the record that has the latest date is chosen.
SELECT
t.*
, u.*
FROM tb_ticket t
INNER JOIN tb_updates u
ON t.ticket_id = u.ticket_id
INNER JOIN (
SELECT
ticket_id
, MAX(updated_at) max_updated
FROM tb_updates
GROUP BY
ticket_id
) mx
ON u.ticket_id = mx.ticket_id
AND u.updated_at = mx.max_updated
;
If you have a dbms that supports ROW_NUMBER() then using that function can be a very effective alternative method, but you haven't informed us which dbms you are using.
by the way:
These rows ARE distinct:
67355;69759;"COMPANY X";"2014-08-22 09:40:21";"OPEN";"John";1
67355;69771;"COMPANY X";"2014-08-26 10:40:21";"UPDATE";"John";1
69759 is different to 69771, and that is enough for the 2 rows to be DISTINCT
there are difference in the 2 dates also.
distinct is a row operator which means is considers the entire row, not just the first column, when deciding which rows are unique.
Used_By_Already's solution would work just fine. I'm not sure on the performance but another solution would be to use cross apply, though that is limited to only a few DBMS's.
SELECT *
FROM tb_ticket ticket
CROSS APPLY (
SELECT top(1) *
FROM tb_updates details
ORDER BY updateTime desc
WHERE details.ticketID = ticket.ticketID
) updates
U Can try something like below if your updateid is identity column:
Select ticketed, max(updateid) from table
group by ticketed
To obtain last row you have to end your query with order by time desc then use TOP (1) in the select statement to select only the first row in the query result
ex:
select TOP (1) .....
from .....
where .....
order by time desc
How can I use a Distinct or Group by statement on 1 field with a SELECT of All or at least several ones?
Example: Using SQL SERVER!
SELECT id_product,
description_fr,
DiffMAtrice,
id_mark,
id_type,
NbDiffMatrice,
nom_fr,
nouveaute
From C_Product_Tempo
And I want Distinct or Group By nom_fr
JUST GOT THE ANSWER:
select id_product, description_fr, DiffMAtrice, id_mark, id_type, NbDiffMatrice, nom_fr, nouveaute
from (
SELECT rn = row_number() over (partition by [nom_fr] order by id_mark)
, id_product, description_fr, DiffMAtrice, id_mark, id_type, NbDiffMatrice, nom_fr, nouveaute
From C_Product_Tempo
) d
where rn = 1
And this works prfectly!
If I'm understanding you correctly, you just want the first row per nom_fr. If so, you can simply use a subquery to get the lowest id_product per nom_fr, and just get the corresponding rows;
SELECT * FROM C_Product_Tempo WHERE id_product IN (
SELECT MIN(id_product) FROM C_Product_Tempo GROUP BY nom_fr
);
An SQLfiddle to test with.
You need to decide what to do with the other fields. For example, for numeric fields, do you want a sum? Average? Max? Min? For non-numeric fields to you want the values from a particular record if there are more than one with the same nom_fr?
Some SQL Systems allow you to get a "random" record when you do a GROUP BY, but SQL Server will not - you must define the proper aggregation for columns that are not in the GROUP BY.
GROUP BY is used to group in conjunction with an aggregate function (see http://www.w3schools.com/sql/sql_groupby.asp), so it's no use grouping without counting, summing up etc. DISTINCT eleminates duplicates but how that matches with the other columns you want to extract, I can't imagine, because some rows will be removed from the result.