2
votes
1answer
27 views

Best way of finding rows referencing a given id on PostgreSQL

I'm trying to find if there would be anything violating the foreign key constraint when deleting a row, to check if I can delete it or not (can't use ON DELETE CASCADE) For that, I have a piece of ...
0
votes
1answer
73 views

Why can't modern databases have unlimited columns [on hold]

I am just curious as to why big open source and commercial RDBMSs can't, don't or won't implement unlimited columns per table? Is there a technical or business reason why this can't be done. MongoDB ...
-1
votes
0answers
23 views

Find the sid of suppliers who supply every red part [on hold]

Suppliers ( sid: integer, sname: string, address: string, country: string ) Parts ( pid: integer, pname: string, color: string, weight: real ) Catalog ( sid: integer, pid: ...
2
votes
1answer
70 views

PostgreSQL return second 'Group' as an array

I have some tables that include websites and visitors and I am trying to write a query that produces a 'top 10' for each site, the tables look something like this... websites ------- website_id (pk) ...
1
vote
1answer
31 views

Linking first and second level composite primary keys

I am trying to create a new database with a hierarchical structure of two many-to-many tables using composite keys. Unfortunately the creation of tables fails stating that the foreign keys do not ...
0
votes
1answer
31 views

How to order by Levenshtein distance?

I want to order a table according to a char field using Levenshtein distance or similar because some entries may contain underscores or grammar errors. It is a table with all the books I plan to read ...
1
vote
0answers
39 views

SELECT query with DISTINCT on a table-structure for graphs is very slow

I have 2 tables where nodes contains about 60m rows and edges about 500m rows (both growing fast). These two tables represent a directed graph. CREATE TABLE edges ( node_from bigint NOT NULL, ...
2
votes
2answers
265 views

Updating every cell of of a table?

I have a table with m columns and n rows. The ETL tools I was using wrote an empty ('') to every cell without a value and I would like them to be NULL instead. This got me thinking if it would be ...
0
votes
1answer
44 views

Use if exists in postgresql [closed]

I know about the exists feature, but that does not help me with the given situation. What I want is: Check if some row exists, and if exists then check for an another row if row exists. Here's ...
0
votes
0answers
18 views

PostgreSQL SELECT and JOIN question [duplicate]

Trying to fix the previous post text formatting issue there was and I did not recognize: I'm using PostgreSQL under ubuntu 14.04. I have two tables as below: create table material_base_name ( ...
1
vote
1answer
39 views

joins with “could be blank” conditions

Question is most probably stupid but I am stuck on this and cant think anymore(Pissed Off). I have these tables-> employee(has a column foreign to location),location and location_flag. And I need ...
1
vote
3answers
60 views

Longest matching suffix while using aggregate functions

Background Looking to find the longest matching string suffix. Setup Consider the following fiddle: CREATE TABLE noun ("label" varchar(10)) ; INSERT INTO noun ("label") VALUES ...
1
vote
1answer
35 views

Tables names in a supertype/subtype schema

I have 3 types of users in my app. The users share some common attributes, but they also have quite a bit of stuff that pertains uniquely to each user type. I have a person table that contains limited ...
0
votes
1answer
40 views

Check for blocked queries periodically and cancel them

I have series of update queries which are executed every 5-10 seconds. Sometimes it happens that one of these will block all the pending update queries as for some reason it just freezes. Since I can ...
2
votes
0answers
41 views

Checking for multiple identical values in a Posgresql array

I have a simple table in Postgresql: CREATE TABLE data (id integer, values integer[]); INSERT INTO data VALUES (1, '{1,2,3,4,5}'); INSERT INTO data VALUES (2, '{1,1,2,3,4,5}'); INSERT INTO data ...
1
vote
2answers
27 views

PostgreSQL - summing arrays by index

I have an array of doubles column (double precision[]) in PostgreSQL that keeps half hour values for a day. So each array holds 48 values. I need an efficient query that is summing all this array ...
1
vote
1answer
31 views

How much should I care about prepared statements for simple queries?

I wonder how much I should care about prepared statements (and therefore try to optimize my code) in case of pretty simple statements. The question originates from the fact that I recently noticed ...
0
votes
0answers
15 views

pgAgent does not run

I referred this to set up a scheduled job and did everything as it mentioned(ran the pgagent.sql as well) I need a very simple task to run periodically. In the 'Definition' tab in the steps, few ...
2
votes
2answers
9 views

PostgreSQL query slows due to ORDER BY even with an index

I have the following query to find offices that service a given area. When I run this query without the "ORDER BY" clause, it takes a less than 0.1 seconds. When I add the ORDER BY clause, it takes ...
1
vote
1answer
16 views

Find the number of where statements that matched in postgresQL

Right now I have a query that looks something like this SELECT id FROM products WHERE products.details->'make' = ? OR products.details->'model' = ? OR products.details->'year' = ...
0
votes
1answer
17 views

How to change the mount point for a column in postgresql table?

This is my scenario I have a table t with following columns id int link varchar(500) name varchar(20) sal text In the link column we will store the location for the pdf files(mount point) ...
0
votes
0answers
20 views

Postgres - Combine similar queries with extra where clause

I am trying to combine a number of fairly time consuming queries into one (if possible) The database contains race-track data that records the times for laps completed by drivers (or users here), the ...
0
votes
0answers
18 views

Recursive query to break time intervals into standard-sized parts

I'd like to write a reusable function which takes 3 arguments a timestamp start_time a timestamp end_time an array of intervals interval_array such that each interval (except the first) divides the ...
0
votes
1answer
17 views

The number of copies for each table stored in physical storage

I am new to Postgres and the database field. My question is that how many copies of each table are stored in physical storage device (memory, disk and so on)? I assume we need more than one copies for ...
0
votes
2answers
46 views

Calculating average with AVG for a list of numbers

This is probably a newbie question (bear with me) but how can I calculate the average for a list of numbers using SQL and the AVG function? I mean, I can add together numbers in SQL like: SELECT ...
0
votes
1answer
56 views

Use serial ID for multiple columns and return it from INSERT

I am using Npgsql and I want to be able to do an insert, and if statement that will do an update and then return a value so when ExecuteScalar is called it reads that value. This was done fine in ...
1
vote
1answer
44 views

Writing a view that caches to another table

I have a table market_trades with columns timestamp, market_id, and amount: api_production=# \d market_trades; Table "public.market_trades" Column | ...
0
votes
1answer
32 views

Postgres get rows where a field stopps growing

I have a table which has the following structure id SERIAL PRIMARY KEY, device_id INT REFERENCES(another_table), uptime TIMESTAMP Every device is pinged every N minutes. The application logic and ...
3
votes
2answers
45 views

idiom to treat empty result set as zero

This is obviously a SSCCE. I have an inventory table that holds the number of items (numOfItems) in a warehouse at any given date (inventoryDate). Both are integers to keep things simple: CREATE ...
0
votes
3answers
118 views

get row count of last select query

I am using a scheduled script which exports the (new) rows of the PostgreSQL database into a textfile. There are also several instances of this script running for several DBs: COPY (SELECT ... FROM ...
2
votes
2answers
57 views

Slow fulltext search due to wildly innacurate row estimates

Fulltext queries against this database (storing RT tickets) seem to be taking a very long time to execute. The attachments table (containing the fulltext data) is about 15GB. The database schema is ...
3
votes
1answer
248 views

Optimizing large database query (25+ million rows, using max() and GROUP BY)

I'm using Postgres 9.3.5 and I have a large table in the database, currently it has over 25 million rows and it tends to get even larger rapidly. I'm trying to select specific rows (all unit_ids with ...
2
votes
2answers
97 views

SQL order by query results in any arbitrary (but reproducible) manner

For testing purposes I need to get some data from a set of database tables in any arbitrary (but reproducible) order. The idea being that I can later compare two runs using a textual diff tool. Is ...
1
vote
1answer
21 views

Handling exceptions from inside a function

I need to add a trigger after insert or update on a table so that, where some row is updated and a certain condition is met, then some other table needs to be updated. However, that last update ...
2
votes
1answer
54 views

PostgreSQL Division In Query Not Working

So I am having a really off day or something, but for the life of me I can not figure this out. I am trying to divide tier1 by total to get a percentage of the total. I thought like this: (tier1 / ...
1
vote
0answers
79 views

Implementing a functionality for processing heavy insertion

I use PostgreSQL 9.1. The scenario is: I receive heavy insertion into Table1 (about 100 rows per sec). For each new row, I have to check the previous and next row of the source table if those are ...
1
vote
1answer
77 views

Best way to add Foreign Key to massive table?

Say I have 4 tables: arrival (~100 million rows), departure (~100 million rows), airport (~30 million rows), airplane (small). arrival and departure each have 2 ForeignKeys: one to airport, one to ...
0
votes
0answers
16 views

Need separate columns that calculates percentage [duplicate]

I have the following table: NAME ------ Alex Bob Bob Tim Alex Roger I need to produce the following: Name Count Percentage ------------------------- Alex 2 33% Bob 2 33% ...
2
votes
6answers
59 views

Need separate columns that calculate percentage

I have the following table: NAME Alex Bob Bob Tim Alex Roger I need to produce the following: Name Count Percentage Alex 2 33% Bob 2 33% Roger 1 16.6% Tim 1 ...
1
vote
1answer
44 views

Upsert statement never completes, infinite loop?

Edit: The function works, tested it by creating a small table. So the problem must be with my input, but I still can't see what the issue is - unless the function is just incredibly slow. It's not a ...
0
votes
1answer
29 views

Bulk insert in multiple tables

I have two tables on which I perform some bulk inserts: key: key_id(pk), key_name related_key: key_id(fk), related_key_id First Insert: values_data = "($$key_1$$), ($$key_2$$)" INSERT INTO key ...
0
votes
3answers
66 views

PostgreSQL equivalent of MySQL query variables?

Is there a straightforward way to adapt these types of MySQL queries to PostgreSQL: setting variables in MySQL like set @aintconst = -333 set @arealconst = -9.999 It seems not. Assigning ...
1
vote
3answers
95 views

Query to return output column names and data types of a query, table or view

Is there a PostgreSQL query or command that returns the field names and field types of a query, table or view? E.g., a solution if applied to simple SELECT query like SELECT * from person should ...
0
votes
2answers
47 views

How to implement a dynamic string into a (prepared) sql statement?

I have some spatial datasets which are available in a open source metadata catalog software GeoNetwork and in a PostGIS database. The problem is that the student who created the database used ...
2
votes
3answers
186 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 ...
0
votes
0answers
10 views

Using range types (with GiST index)

Say I have 2 tables with a PostgreSQL range column: CREATE TABLE events ( id serial, during tsrange ); and CREATE TABLE storms ( id serial, during ...
0
votes
1answer
23 views

Row-level subquery caching?

I have a query that uses a CTE which contains millions of rows. I plan to call this query many times, and the CTE returned each time will have most of the same rows. Is it possible for me to cache the ...
1
vote
1answer
21 views

Index on integer column not helping. Help? (EXPLAIN ANALYZE output inside)

The table market_trades has an integer column market_id which takes values from 1 to 5. This seems like a pretty straightforward query to get the number of trades on each market: WITH markets AS ( ...
1
vote
1answer
42 views

Optimizing a query on a large table (EXPLAIN ANALYZE result inside)

I have a table market_trades with a timestamp column: api_production=# \d market_trades; Table "public.market_trades" Column | Type ...
2
votes
4answers
101 views

Make IN clause behave like AND clause

I've asked the same question on stackoverlow, but got no answer, so that's why I'm asking it here (I've read that simple sql questions should be asked at SO, but I have no choice). Suppose I have 3 ...