A core SQL statement, SELECT retrieves data from one or more tables or other sources of row set data such as views or table-valued functions.

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2
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2answers
5k views

How to COUNT number of rows with LIMIT?

I want to catch X rows, thus, I set LIMIT X; but how can I simultaneously count the total number of rows too? Currently, I use two separate queries to do so as SELECT COUNT(*) FROM col WHERE CLAUSE ...
5
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1answer
69 views

How to Choose Between VALUES and SELECT for INSERT?

This answer raised the question for me how to choose between VALUES and SELECT in such a function . Using PostgreSQL 9.4.3 on x86_64-unknown-linux-gnu, compiled by gcc (Debian 4.9.2-10) 4.9.2, 64-bit: ...
6
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4answers
34k views

Getting SELECT to return a constant value even if zero rows match

Consider this select statement: SELECT *, 1 AS query_id FROM players WHERE username='foobar'; It returns the column query_id with value 1 along with a player's other columns. How would ...
0
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2answers
140 views

using update query with subquery in Oracle sql

I have an update query where I am trying to update a field but for more than one record, I am trying a join but it doesn't work. Below I get multiple values that come back from the select statement ...
2
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2answers
166 views

How do I set the isolation level for SELECT statement?

Using PostgreSQL 9.5 I would like to make sure that when I run a SELECT statement I get consistent results, i.e. if the table is modified while the SELECT is running, I want to get the state that was ...
1
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2answers
20 views

How to select distinct record?

I have a table, as follows: ID | Name | MyID 1 | Alan | 2 2 | Alan | 2 3 | John | 3 I want to select the records as follows: If two records have the duplicate ...
1
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1answer
214 views

Select all from table using procedure oracle

I am trying to execute the select command in a procedure.Initially i retrived all of the columns of the table in the procedure using cursor. The real problem comes when I am trying to access the ...
1
vote
1answer
317 views

Speeding up a simple select query on Mariadb

I have a 100k rows table with the following structure: +----------+------------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | ...
2
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3answers
1k views

Getting the top count of records from a table for each month and user

I have a table where translations are stored along with the user_id and when the translation was added. I want to create a query that shows the 'Translator of the month' (the person who did the most ...
8
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2answers
36k views

SELECTing multiple columns through a subquery

I am trying to SELECT 2 columns from the subquery in the following query, but unable to do so. Tried creating alias table, but still couldn't get them. SELECT DISTINCT petid, userid, (SELECT ...
4
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2answers
58 views

MySQL - Order by closest value on multiple columns

I have a table for a game lobby. In this lobby a user gets put in their connection and their level. In my SQL statement I am getting all the users in the lobby which are between +5/-5 of the user's ...
1
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1answer
59 views

Vertica performance on select from view with union

We have a huge number of rows(tens of millions), and for each table we have an associated view that is a select with UNION ALL between that table and several others. Now, we are doing a select from ...
0
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1answer
121 views

Need help in incrementing the date in oracle

Error thrown as "Invalid number" while trying to increment the date. Given below is the query executed through sqlplus. Please help me on this. select ''''||to_date(:To_date, 'dd-mon-yyyy')+1||'''' ...
3
votes
3answers
76 views

SELECT + INSERT or INSERT alone

I have an application where several devices send data every second to my server. On the database I have a table with the devices and another table with the data sent every second. The first time a ...
2
votes
5answers
20k views

Retrieving row count without using Count function

I wrote a query below which shoots me a syntax error why would it do so, SELECT MAX('Row') FROM (SELECT ROW_NUMBER() OVER(ORDER BY ID DESC) 'Row' FROM USERS) Error Desc: Incorrect syntax near ...
1
vote
1answer
111 views

how to cache a subset for cascading select queries in mysql

Here is another database problem I stumbled upon. I have a date-range partitioned MyIsam look-up table with 200M records and ~150 columns. On this Table I need to perform cascading SELECT-Statements ...
0
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2answers
136 views

Remove duplicates from multiple joins

I'm using WordPress $wpdb->get_results for this query (it is simplified for question purposes): SELECT customer.id, customer.name, address.address appt.appointment_date, pay.date FROM customers ...
4
votes
1answer
151 views

Mysql: Problem using GREATEST with IFNULL and join

I have a query selecting the greatest value of 2 timestamps. To achieve it I'm calling: SELECT GREATEST( IFNULL( tableb.create_time, 0 ) , IFNULL( tablea.create_time, 0 ) ) I'm using IFNULL ...
0
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1answer
464 views

Restrict access to rows by usename

In my database i store data of different users (e.g. addresses or invoices) in the corresponding tables. I want to make sure that a logged in user only has access to it's own data in the tables (so ...
3
votes
2answers
25 views

Howto (async?) preview intermediate resultset

Is it possible to retrieve parts of the resultset from SQL Server queries in advance? For instance if I run a query that will return 20,000 rows, is it possible to throw the results in packages of ...
2
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1answer
57 views

How to get number of active users with one SQL-Query?

I am running a site similar to craigslist where users can create classifieds and write/reply messages. In order to get an idea of activity I would like to get the amount of active users per month. ...
3
votes
1answer
64 views

SQLite Like clause match whole word only

I have a SQLite database with a table named: minecraft +----+----------------------+ | id | name | +----+----------------------+ | 1 | Pocket Mine MP | | 2 | Open Computers ...
8
votes
4answers
27k views

How to do a case sensitive search in WHERE clause?

I want case sensitive search in SQL query. But by default, MySQL does not consider the case of the strings. Any idea on how to do a case sensitive search in SQL query?
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0answers
36 views

Fetch items where related rows has different values

I have table in MySQL called attributes, and other table, attribute_values, one attribute can have multiple values, values identified by context attribute and has value_c attribute wich contain value. ...
1
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1answer
27 views

Cities and States (a few data): single table or splitted?

I am designing a DB schema and I need to store cities and states. I expect only a few rows, let's say, 20 cities. Example: id | city | state 1 | Rio de Janeiro | RJ 2 | Niteroi ...
1
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1answer
40 views

How to select data from differents servers with a single query?

I have a challenge! I need select from 4 different tables from 4 different servers. Example: Select * from server1.tableS1.sys.view Select * from server2.tableS2.sys.view Select * from ...
2
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2answers
98 views

Select random rows up to a limit

SELECT * FROM my_players WHERE player_type = 'IF' ORDER BY cardweight / rand() DESC limit 3 That is my current query, What I am trying to do is select random rows for which I have the * in my query, ...
4
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2answers
175 views

Query parent table and get child tables columns

I have two tables, one inherits the other: CREATE TABLE parent ( col1 INTEGER ); CREATE TABLE child ( col2 INTEGER ) INHERITS( parent ); // Insert some data INSERT INTO parent( col1 ) ...
2
votes
2answers
47 views

Search multiple values in multiple columns

I have a table results with this fields: id results_id number_one (int) number_two (int) number_three (int) number_four (int) number_five (int) Each number_* column can contain a number from 01 to ...
1
vote
1answer
23 views

SELECT with equal chance between same IDs - MySQL

How can I SELECT data with equal chances for same IDs in MySQL (for php). For example, assume below data structure: id value 1 alfa 1 beta 1 gamma 2 hello 2 bye 3 sky I want ...
0
votes
1answer
18 views

How can I access certain information from YQL?

I notice the YQL commands such as select * from yahoo.finance.quote where symbol in ("YHOO") return all the data for that certain stock. I was wondering is it possible to access data from YQL ...
2
votes
3answers
1k views

How to query efficiently from Postgres to select special words?

Let's say that I have a table called words with very many records. Columns are id and name. In the words table I have for example: 'systematic', 'سلام','gear','synthesis','mysterious', etc. NB: ...
1
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1answer
146 views

Alternatives to Linked Servers (Allow Inline SQL with Parameters)

I am trying to find a solution to execute inline SQL with parameters against some linked server databases. From what I have found online the only proper way to query a linked server is to use ...
3
votes
2answers
38 views

Get rows with minimum value

I have tables company: company_id | - - - - - - - - - - - - - - 1 | 2 | employee: employee_id | - - - - - - - - - - - - 1 ...
2
votes
1answer
37 views

Join two SELECT results with the same post_id value

I need to do a query to the MySQL database of my site built in WordPress / WooCommerce. The 'wp_posts' table keeps products, articles and more. Every row in 'wp_posts' has a 'post_id' to connect ...
1
vote
3answers
272 views

REPLACE INTO SELECT from table

Is there a way in DB2 to replace the entire table with just selected rows from the same table ? Something like REPLACE into tableName select * from tableName where col1='a'; (I can export the ...
4
votes
2answers
72 views

Indexed but still slow during query

I have a table that stores REST requests and responses: CREATE TABLE ws_call_logs ( id BIGINT NOT NULL, ws_method_id BIGINT NOT NULL, device_id ...
5
votes
2answers
66 views

Same record shows up multiple times in ordered paginated query

Some records show up on multiple result "pages" with the following query: SELECT `description`, `wallpaper` FROM `bbr_bar` WHERE `country_id` = '2510769' ORDER BY `online` DESC ...
39
votes
8answers
9k views

Is select * still a big no-no on SQL Server 2012?

Back in the days of yesteryear, it was considered a big no-no to do select * from table or select count(*) from table because of the performance hit. Is this still the case in later versions of SQL ...
5
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2answers
67k views

Using SELECT in the WHERE clause of another SELECT

I have made a draft remote application on top of libpq for PostrgreSQL. It behaves well, but I have profiled the general functioning of the application. For each final business result that I produce, ...
0
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0answers
31 views

Display Complete Month With or Without TIMESTAMP field

Please edit the title if you have a better, I didn't find other words to describe this. Environment Fields: |id|time|text| Situation I have to make a report with the total of records per day, ...
0
votes
1answer
47 views

MySQL: Select two values of two columns and compared their values exchanging them each other

I need to find a way to select one random row where the subscriber is not also leader (in the same or any other row). Something like this: (just to have an idea) SELECT `leader`,`subscriber` FROM ...
2
votes
2answers
56 views

CTE To Use Alternate Select When Select Returns No Rows

I have created a involved CTE, no recursion, with multiple selects being done as it processes the business logic of the requirement. But I have been advised that the logic needed for the scenario ...
1
vote
1answer
41 views

Unknown column 'actions_in_group' in 'field list'

I keep getting: Unknown column 'actions_in_group' in 'field list' Here's the SQLFiddle: http://sqlfiddle.com/#!9/4ddf0/19 SELECT *, SUM(actions_in_group) AS total_rows_in_group, ...
0
votes
2answers
36 views

Combining two similar queries into one (PostgreSQL)

I have 2 queries like this: SELECT c.id FROM component c, base_vee bv WHERE c.id IN (SELECT component_id FROM registry_row WHERE registry_id = 199) AND c.id = ...
0
votes
1answer
90 views

Simple select query taking too long

I have been having a hard time with this query, I have a webpage which is supposed to run this query a dozen of times, and with an execution time up to 40 - 50 seconds per query, you can see how this ...
2
votes
2answers
3k views

Insert into … (…) (Select…) on duplicate key update

Can you help me to solve a problem. The task is to insert a record in MySQL database. terms: If the record exists - to update the record. If the record does not exist - to create a new one. ...
0
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1answer
54 views

Efficient way to get last 10 rows of each group in SQLite, can CTE help?

Consider there is a table of job runs history with the following schema: job_runs ( run_id integer not null, -- identifier of the run job_id integer not null, -- identifier of the job ...
0
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1answer
142 views

CONCURRENT SELECT's SLOW … LOCK IN SHARE MODE

My Table has 25 Million rows total and 6 million rows satisfying below where clause. Select 1: select max(stamp) from Table where type = "string" LOCK IN SHARE MODE ; 6000+ seconds Select 2: ...
2
votes
1answer
23k views

How do I select items from a table where a single column must contain two (or more) values?

I have a MySQL database table that references different words and their locations in documents. I want to return the IDs of documents that contain all of the words. Here is an example table. docid ...