The tag has no wiki summary.

learn more… | top users | synonyms

0
votes
1answer
50 views

What is the best query to get the latest row version based on time?

I'm wondering what can be the most efficient query to get the latest rows from the following table. CREATE TABLE AGE_DATA ( INSERTED_DAY TIMESTAMP(6), HOSTNAME VARCHAR2(255 CHAR), CONCEPT ...
2
votes
3answers
126 views

Aggregate query with min

Having a product_stock table with following structure: product_id warehouse_id stock price Which has bunch of records (same product can be in different warehouses): 1, 1, 0, 500 1, 2, 5, 505 1, 3, ...
4
votes
1answer
305 views

Subselect of MAX(Version) takes many minutes, though there are only ~20K records

I have a pretty complicated data model. I can't understand most SQL examples without an explanation of what's being modeled, so I'll try to explain. Mainlines -> Releases -> Overlays -> Calibrations ...
0
votes
0answers
11 views

Postgres Join that allows for an empty table [migrated]

I have the following schema, and I'm having a lot of trouble joining these tables properly. I'm trying to get all folders that don't have a file updated in the last 10 mins in them. But I want to ...
1
vote
1answer
40 views

Select all most recent records

I have this two tables (and their main fields): Target: Message: Id IdMessage Id IdMain IdReply DatePosted ================ ...
1
vote
2answers
67 views

Efficient query to get last row group by multiple columns

I have a table like the following: spread_id serial NOT NULL, game_id integer NOT NULL, sportsbook_id integer NOT NULL, spread_type integer NOT NULL, spread_duration integer NOT NULL, home_line ...
3
votes
2answers
52 views

Selecting minimum value in top grouping only

I have a query built in Oracle 10 which produces a set of data like this: EMP_ID WORK_DT TIME_TYPE ---------- --------- --------- 12345 19-DEC-14 10 12345 18-DEC-14 10 ...
1
vote
1answer
42 views

How to Select the First (or last) entry for a specific day

I have a table "AttendanceRecords" with entries like this EntryID UUID PRIMARY KEY, StafID UUID REFERENCES staffmembers(ID) NOT NULL, ArrivalTime TIMESTAMP NOT NULL, DepartureTime TIMESTAMP For one ...
31
votes
6answers
1k views

Retrieving n rows per group

I often need to select a number of rows from each group in a result set. For example, I might want to list the 'n' highest or lowest recent order values per customer. In more complex cases, the ...
-1
votes
2answers
299 views

How to select top 10 records from each category

I have a table with fields Hour, PathId, Duration, Event, CellId, Channel I have 50+ CellId. Each CellId has four PathId (i.e. 0, 1, 2, 3). Each PathId has many Events and Durations. Now I want to ...
0
votes
1answer
32 views

Query with column data for a max

In Postgres, I have a table like this: Column | Type | Modifiers ...
0
votes
2answers
67 views

Find the last visit by teacher and show the rest of columns in MySql

I would like to group the teachers by the last visit and show the other values corresponding to the last visit. CREATE TABLE IF NOT EXISTS `visits` ( `FIELD1` int(5) NOT NULL, `teacher` varchar(9) ...
0
votes
3answers
100 views

Get latest status of an item in the database

I have this table: ID|Item-FK |timestamp|status ============================= 1 | 123 | ... | OK 2 | 123 | ... | FAILED ... I want to query get all items which last status was FAILED. ...
2
votes
2answers
1k views

Join 3 tables and return only distinct values for max datetime

I've been trying to do this the whole 2 weeks but seems like to no avail. 3 tables involved here. but am expecting the result would be distinct case no. for the same date & user. otherwise, it ...
1
vote
0answers
52 views

Selecting most recent date when dates are stored in another table

Working in a MySQL database, I have tables set up like this: Table song_instances has song_id (int), meeting_instance_id (int) The meeting_instances table has columns meeting_instance_id (int), ...
-1
votes
1answer
96 views

Select latest record for each ID

I have three tables that contains data as below: Users Id Name Other_Columns --------------------------- 1 John Blah 2 Ricky Blah 3 Stella Blah 4 Bob Blah Saldo Id ...
2
votes
3answers
3k views

GROUP BY one column, while sorting by another in PostgreSQL

How can I GROUP BY one column, while sorting only by another. I'm trying to do the following: SELECT dbId,retreivalTime FROM FileItems WHERE sourceSite='something' GROUP BY seriesName ...
3
votes
2answers
640 views

Are ORDER BY clause & ROW_NUMBER duplicating functionality when I need top n queries

I have a table that tracks violations for a student. I want to count the number of violations and select top 2 violators from each class. The query would look like this SELECT * FROM ( SELECT ...
2
votes
1answer
88 views

Why am I getting different results from a query vs. a view

The base problem I'm facing is that I need the latest record for each item. A little setup... MySQL 5.6.14. I need to create two views (because MySQL won't let me have a subquery in a view). My ...
0
votes
1answer
54 views

group by and display contents of last row for each result

I've got some data of two objects and I want to retrieve the last row of both the objects, preferably in one query. Table structure: CREATE TABLE data ( pid serial NOT NULL, dt timestamp without ...
4
votes
2answers
290 views

select specified number of unique IDs where second column is unique

Look at the following example starting from the top row (id=9) and work your way down, selecting a limit of 4 rows that have sec's that we have not yet seen. We "select" id=9 because we don't yet have ...
1
vote
1answer
54 views

Consolidating large table

I need some help with a complex query. Table def: Table "public.agent_log" Column | Type | Modifiers ...
2
votes
1answer
351 views

Find the second highest value from a subquery or derived table

I have a subquery which returns the following results. 'c003', '120000.00' 'c002', '90000.00' 'c001', '20000.00' 'c005', '8000.00' 'c004', '5000.00' I want to find the second highest value from ...
1
vote
2answers
217 views

optimization of expensive subquery

The following query gets the last report (where latitude and longitude and secs are <> 0) associated with the specified units: SELECT reports.* FROM reports INNER JOIN ...
1
vote
2answers
68 views

Nearest value for each foreign key

I have a table with a primary key, timestamp, value, foreign key. I would like to find the nearest value to a timestamp for each of the foreign keys in a list. Unfortunately, the gap from the given ...
2
votes
2answers
236 views

UPDATE table with another table data

I want to update the table car_check field fencing.(total 40 rows).I also use postgis function. I think it's a little difficult.Any suggestions? The code is the first carid example. UPDATE car_check ...
8
votes
2answers
6k views

Efficient query to get greatest value per group from big table

Given the table: Column | Type id | integer latitude | numeric(9,6) longitude | numeric(9,6) ...
22
votes
6answers
25k views

How do I efficiently get “the most recent corresponding row”?

I have a query pattern that must be very common, but I don't know how to write an efficient query for it. I want to look up the rows of a table that correspond to "the most recent date not after" the ...
1
vote
2answers
36k views

Select which has max date or latest date

Here are two tables. SCHOOL_STAFF SCHOOL_CODE + STAFF_TYPE_NAME + LAST_UPDATE_DATE_TIME + PERSON_ID ================================================================= ABE Principal ...
3
votes
2answers
7k views

How group with min(date) and select an another column in the same table

I have a query who return something like it : Name Gender Job date of hire John M mechanic 2012-05-08 John M electrician 2010-01-01 Vicky F scientific 2012-11-11 Bob ...
13
votes
5answers
64k views

How to select the first row of each group?

I have a table like this: ID | Val | Kind ---------------------- 1 | 1337 | 2 2 | 1337 | 1 3 | 3 | 4 4 | 3 | 4 I want to make a SELECT that will return just the ...