I am trying to get the maximum date out of multiple tables when those table have a particular geometry.
My tables more or less look like that (of course they're all different but I shortened them in order to make it clearer ):
A table type :
Id, Info, Geometry, Date
And finally I have an other table that looks like that (shortened again) :
B table:
Id, Geometry
Now, what I want to do is to join all my A type tables on Geometry where they intersect with the B table Geometry, and to get the A table that has the most recent date.
I currently have the following request which is working:
UPDATE last_updateT SET date_last_update= S.dateMax
FROM
(SELECT B.gid, MAX(A.last_date) AS dateMax
FROM B
JOIN A ON ST_Intersects(B.geometry, A.geometry)
GROUP BY B.gid) S
WHERE T.id = S.gid;
Now I'd like to be able to do that kind of join on multiple table that looks like table A. I've heard of the function GREATEST but I am not sure about how to use it.
Also, I use Postgresql if that makes any differences.
It seems you are looking for UNION ALL, so you can treat the data from different tables as if it were data from only one table:
SELECT
b.gid,
MAX(x.last_date) AS dateMax
FROM b
JOIN
(
SELECT geometry, last_date FROM a
UNION ALL
SELECT geometry, last_date FROM aa
UNION ALL
SELECT geometry, last_date FROM aaa
) x ON ST_Intersects(b.geometry, x.geometry)
GROUP BY b.gid;
In broad strokes, MAX is an aggregate function, so you use MAX to get the highest value from the same column over a number of different rows.
GREATEST is a scalar function, you use GREATEST to get the highest value from different columns in the same row.
eg:
SELECT GREATEST(col1,col2,col3)
Greatest: https://www.postgresql.org/docs/9.5/static/functions-conditional.html
Max: https://www.postgresql.org/docs/9.5/static/functions-aggregate.html
Related
I have the following table structure:
VEH_GRP VEH_CODE_IND CATEGORY DATE Mileage_1 Mileage_2
1 A CAR 31-May-08 10
1 B CAR 31-May-08 100
How can I use a sql query to combine them into 1 row? Ideally I would want to perform computation to divide Mileage_1 over Mileage_2..
Thanks everyone.
You would need to use a self join to combine two rows based on some criteria like which 2 rows you require to be combined.
Example :
select
t1.*,t2.* ,t1.mileage_1/t2.mileage_2
from
data_table t1
inner join
data_table t2
on
t1.veh_grp = t2.veh_grp
Also, you'll need to think of some logic to select which row should represent t1 and which should represent t2.
You can use aggregation. I'm not quite sure what the results would look like but:
select VEH_GRP, CATEGORY, DATE,
SUM(Mileage_1), SUM(Mileage_2),
SUM(Mileage_1) / SUM(Mileage_2)
from t
group by VEH_GRP, CATEGORY, DATE;
First time posting here, hopes it goes well.
I try to make a query with Oracle SQL Developer, where it returns a customer_ID from a table and the time of the payment from another. I'm pretty sure that the problems lies within my logicflow (It was a long time I used SQL, and it was back in school so I'm a bit rusty in it). I wanted to list the IDs as DISTINCT and ORDER BY the dates ASCENDING, so only the first date would show up.
However the returned table contains the same ID's twice or even more in some cases. I even found the same ID and same DATE a few times while I was scrolling through it.
If you would like to know more please ask!
SELECT DISTINCT
FIRM.customer.CUSTOMER_ID,
FIRM.account_recharge.X__INSDATE FELTOLTES
FROM
FIRM.customer
INNER JOIN FIRM.account
ON FIRM.customer.CUSTOMER_ID = FIRM.account.CUSTOMER
INNER JOIN FIRM.account_recharge
ON FIRM.account.ACCOUNT_ID = FIRM.account_recharge.ACCOUNT
WHERE
FIRM.account_recharge.X__INSDATE BETWEEN TO_DATE('14-01-01', 'YY-MM-DD') AND TO_DATE('14-12-31', 'YY-MM-DD')
ORDER
BY FELTOLTES
Your select works like this because a CUSTOMER_ID indeed has more than one X__INSDATE, therefore the records in the result will be distinct. If you need only the first date then don't use DISTINCT and ORDER BY but try to select for MIN(X__INSDATE) and use GROUP BY CUSTOMER_ID.
SELECT DISTINCT FIRM.customer.CUSTOMER_ID,
FIRM.account_recharge.X__INSDATE FELTOLTES
Distinct is applied to both the columns together, which means you will get a distinct ROW for the set of values from the two columns. So, basically the distinct refers to all the columns in the select list.
It is equivalent to a select without distinct but a group by clause.
It means,
select distinct a, b....
is equivalent to,
select a, b...group by a, b
If you want the desired output, then CONCATENATE the columns. The distict will then work on the single concatenated resultset.
I have a table which contains more than one row for a particular value . Here is the table structure:
NAME,NUMBER,STATUS,DESC,START_DATE,END_DATE
A,3,X,DetailsOfX,13-10-15,13-10-15
A,2,Y,DetailsOfY,13-10-15,13-10-15
A,2,Z,DetailsOfZ,13-10-15,13-10-15
A,1,X,DetailsOfX,12-10-15,12-10-15
The output i need is i.e.
A,3,X,DetailsOfX,13-10-15,13-10-15
A,2,Y,DetailsOfY-DetailsofZ,13-10-15,13-10-15
A,1,X,DetailsOfX,12-10-15,12-10-15
So basically i want to select one of two or more rows from a table with data from columns from both the rows (in bold above). The query below i tried using JOIN returns 4 rows.
SELECT A.NAME,A.NUMBER,B.STATUS,A.DESC||"-"||B.DESC,A.START_DATE,A.END_DATE
FROM TABLE A
JOIN (SELECT NUMBER,STATUS,DESC,START_DATE,END_DATE FROM TABLE WHERE NAME='A') B
ON A.NAME=B.NAME AND
A.NUMBER=B.NUMBER
Can somebody help me with the query that would work.
Thanks
If you are using IBM i 7.1 (formerly known as OS/400), you should be able do this with two tricks: hierarchical queries, and XML functions.
See my tutorial under Q: SQL concatenate strings which explains how to do this on DB2 for i in order to merge the descriptions.
GROUP BY any fields by which you would want rows combined into one, but all other columns must be the result of an aggregate function. So for example, if you want one row per name, number, but have various values for Status, StartDate, EndDate, then you will need to say something like min(Status), min(StartDate), max(EndDate). Is the minimum status code actually the one you want to report?
If your OS is at version 6.1, you may still be able to use a conventional recursive query (or under v5r4), but you might need an addtional CTE (or two?) to concatenate the descriptions.
You need to use GROUP BY and FOR XML PATH:
SELECT
X.NAME, X.NUMBER, X.STATUS,
STUFF((
SELECT '-' + [Desc] AS Desc
FROM YourTable Y
WHERE Y.ID = X.ID
FOR XML PATH(''),TYPE),1,1,'') AS DescValues,
StartDate,
EndDate
FROM YourTable X
GROUP BY Name, Number, Status, StartDate, EndDate
This is assuming you want separate rows for any differences in name, number, status, start date, or end date.
Also, this is assuming SQL Server.
I want to check my database for records that I already have recorded before making a web service call.
Here is what I imagine the query to look like, I just can't seem to figure out the syntax.
SELECT *
FROM (1,2,3,4) as temp_table
WHERE temp_table.id
LEFT JOIN table ON id IS NULL
Is there a way to do this? What is a query like this called?
I want to pass in a list of id's to mysql and i want it to spit out the id's that are not already in the database?
Use:
SELECT x.id
FROM (SELECT #param_1 AS id
FROM DUAL
UNION ALL
SELECT #param_2
FROM DUAL
UNION ALL
SELECT #param_3
FROM DUAL
UNION ALL
SELECT #param_4
FROM DUAL) x
LEFT JOIN TABLE t ON t.id = x.id
WHERE x.id IS NULL
If you need to support a varying number of parameters, you can either use:
a temporary table to populate & join to
MySQL's Prepared Statements to dynamically construct the UNION ALL statement
To confirm I've understood correctly, you want to pass in a list of numbers and see which of those numbers isn't present in the existing table? In effect:
SELECT Item
FROM IDList I
LEFT JOIN TABLE T ON I.Item=T.ID
WHERE T.ID IS NULL
You look like you're OK with building this query on the fly, in which case you can do this with a numbers / tally table by changing the above into
SELECT Number
FROM (SELECT Number FROM Numbers WHERE Number IN (1,2,3,4)) I
LEFT JOIN TABLE T ON I.Number=T.ID
WHERE T.ID IS NULL
This is relatively prone to SQL Injection attacks though because of the way the query is being built. It'd be better if you could pass in '1,2,3,4' as a string and split it into sections to generate your numbers list to join against in a safer way - for an example of how to do that, see http://www.sqlteam.com/article/parsing-csv-values-into-multiple-rows
All of this presumes you've got a numbers / tally table in your database, but they're sufficiently useful in general that I'd strongly recommend you do.
SELECT * FROM table where id NOT IN (1,2,3,4)
I would probably just do:
SELECT id
FROM table
WHERE id IN (1,2,3,4);
And then process the list of results, removing any returned by the query from your list of "records to submit".
How about a nested query? This may work. If not, it may get you in the right direction.
SELECT * FROM table WHERE id NOT IN (
SELECT id FROM table WHERE 1
);
By "fixed vector" I mean a static list of values, like 1 through 24.
The current query looks like this (simplified)
SELECT Period, Profit FROM Projections
But the data is "sparse" — so there's not a row for every period.
What query will give me a row for peiods 1-24 every time, with zeros (or NULLs) where there's no data?
I would like to do this with just the query to avoid a mess of client code.
Thanks!
You could make a udf called udfRange(start int,count int) or something like that, and left-join to the output of the function.
Or for something really quick and dirty, you could join to a subselect that looked like
SELECT DATA.Period, P.Profit
FROM (
SELECT 1 AS Period
UNION SELECT 2
...
UNION SELECT 24) AS DATA
LEFT JOIN Projections P ON DATA.Period = P.Period
Why not create a 'Periods' lookup table, with values 1 - 24 (and any other columns that might be relevant, like a description of the period, or its name) then do a left outer join between the Periods lookup table and your projections table.