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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Selecting multiple columns from multiple rows in one column (subquery?)

I'm working with MySQL 5.1.68. I have a situation where I'd like to select rows from another table into a column. I'd like to output this: id # name # citizen_name (multiple citizen names) 1 # ...
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4k views

How to run a SELECT query within while loop in PHP?

Within a SELECT query via PHP while loop, I need to run a mysql SELECT query as $result1 = $mysqli->query("SELECT * FROM table1"); while ( $row = $result->fetch_assoc() ) { if ( $row['X'] == ...
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435 views

Select records that do not have associations outside a certain list

I have a mySQL table of nodes and each node can be associated with many categories. I have a list of category ids that are acceptable (498, 499). I want to select only nodes who do not have ...
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231 views

I would like to query a range of criteria on multiple columns in MySQL

I have 3 columns in a mysql table. I'm using Innodb engine. I want to be able to search for some values on those columns and also anything close to those values. For example : We have 3 columns as ...
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362 views

How to re-arrange rows to best fit within groups?

I categorized a table with the method introduced here to categorize my items to folders with a limit size of 100. mixing_order id num_items cat order_in_cat cumulative_sum folder 1 ...
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3k views

How do I perform a UNION query on a dynamic list of tables?

My database has an unknown amount of tables, named with the same prefix followed by a random string: _ct_<random_string>. Each of these tables has the same data structure. I also have another ...
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74 views

How can I query to do this?

I have 2 tables, in feeds I have my feeds and (feeds.ID) is the primary key. second table is items. and feeds.ID is realted to items.feed_ID, so with a simple inner join i can extract the data of each ...
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289 views

Shift db data to another column

I have the following table id | ev_id | ev_loc_id | a | b | prev_a | prev_b If I the (ev_id AND ev_loc_id) not exist in the table then I just insert them, otherwise I'm putting ...
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33 views

Row locks on selects

select t.*, row_number() over ( partition by t.Entity_Identifier order by t.Message_Sequence ) as seqnum from Process_Activity t (ROWLOCK) where t.Process_Id = Is it possible for ...
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145 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 ...
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60 views

MySQL select with join table

I have 3 tables, one of them is join table: user table: CREATE TABLE `user` ( `id`, `name`) media table: CREATE TABLE `media` ( `id`, `value`, `type` enum('M', 'T')) user_media table: CREATE ...
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72 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 ...
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132 views

Reference column alias in same SELECT list

I'm converting an old MS-Access-based system to PostgreSQL. In Access, fields that were made up in SELECTs could be used as parts of equations for later fields, like this: SELECT samples.id, ...
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79 views

How to insert the gathered dates into another table using INSERT SELECT in MySQL?

insert into rfdate (date) select adddate('1970-01-01',t4*10000 + t3*1000 + t2*100 + t1*10 + t0) selected_date from (select 0 t0 union select 1 union select 2 union select 3 union select 4 union select ...
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47 views

How to use the value from record like as varchar?

I'm trying update a old table with result of selec for another tables but get a error using this sintaxe (e.g.): DO $$ DECLARE _roles refcursor; _onerole varchar; _record RECORD; ...
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134 views

two column compare ,get count(*) of two column A value same cloumn B value

I have a Mysql table as --------------------- -- page - user -- --------------------- -- page a - user 1 -- -- page a - user 2 -- -- page a - user 3 -- -- page b - user 1 -- -- page b - user 3 -- ...
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179 views

What is wrong with this SELECT query? No errors, no results

Haunted by this MySQL query that refuses to return results: select entity_id from customer_entity where entity_id NOT IN (SELECT sfo.customer_id FROM sales_flat_order sfo); If you divide the two ...
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232 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 | ...
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68 views

Slow Query with LIMIT

We have this query: SELECT "messages".* FROM "messages" WHERE "messages"."account_id" = 1 AND "messages"."status" = 'unread' AND (created_at >= '2014-04-24 01:00:00.000000') ORDER BY id DESC It ...
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79 views

Select all foreign key relationship chains from any set of potentially gapped table names

I am using this query to find all foreign key relationships: SELECT con.relname AS child_table, att2.attname AS child_column, cl.relname AS parent_table, att.attname AS parent_column ...
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190 views

use variable to determine the name of a column in the select in postgre

I'm trying create a update for a new structure of tables from a old table, but not using functions. I'm trying create a script to it. The old table is like this: -- old table (OldTable) name| col_a | ...
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95 views

Mysql: Problem using GREATEST with IFNULL and join

I have a query selecting the greatest value of 2 timestamp. To Achieve it I'm calling: SELECT GREATEST( IFNULL( tableb.create_time, 0 ) , IFNULL( tablea.create_time, 0 ) ) I'm using IFNULL because ...
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Multiple selects ordering desc from single table

I'm trying to do multiple selects to give multiple ordered columns. I'm struggling to get the below mysql query to achieve the output I want. SQLfiddle: http://www.sqlfiddle.com/#!2/a1002/3 ...
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SELECT, PROJECT, CARTESIAN PRODUCT and JOIN

I have the following tables; DOG +----------------------------------------------+ | Name Type Age Kennel_name Owner_name | +----------------------------------------------+ ...
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How to join the tables in mysql to get wall messages and comments with name of person ? Only user and his friends messages

I have four tables in my mysql database as shown in the image url provided. I want to select data from the tables without duplication. I want to show messages and comments on wall according to the ...
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57 views

SELECT showing two COUNTs

I had this table: tblA id | name | value 1 nameA 1 2 nameA 0 3 nameB 0 4 nameC 0 5 nameC 1 6 nameC 1 As you see, Value can be 1 or 0 I need to perform a query ...
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880 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 ...
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79 views

Mysql with index [closed]

I have this following sentence: SELECT Day(C.DataCadastro) AS Dia, Month(C.DataCadastro) AS Mes, Year(C.DataCadastro) AS Ano, COUNT(I.Plano) AS Total FROM clientes AS C ...
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532 views

Merge 2 tables and fetch data one by one

I have two tables: product & offers. products has (prod_id, category_id, prod_name, brand, price, status) offers has (offer_id, prod_id, offer_type, discount_amt, validity) I want to display ...
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281 views

MAX (id) function with MySQli

How can I use the following statement to return only the record with the maximum PersonID from the table? /* Create the prepared statement */ if ($stmt = $mysqli->prepare("SELECT Max(PersonID) AS ...
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547 views

Can a RDBMS connect to a remote server, execute a select query and copy them into a local table just with SQL commands?

I'm sorry it may sound stupid but I've been wondering about how multiple databases are automated before the virtualization era. Can a DB Adminsitrator make a stored procedure to get data from a remote ...
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44 views

Work with table named Group [closed]

I have a table named Group in my database , when I try to work on it it gave error : SELECT GroupID,GroupName FROM Group it said : Msg 102, Level 15, State 1, Line 1 Incorrect syntax ...
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822 views

How to mix pairs of rows without JOIN (in a temporary table)?

I have a TEMPORARY table containing pairs of key/value as id col1 col2 type pair 1 key1 key2 key 1 2 value1 value2 value 1 3 key3 ...
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39 views

Postgres: Disable “similarity” column output on “SELECT SIMILARITY”?

I've tried disabling similarity column output on SELECT SIMILARITY but still cannot. Below query will generate a column similarity: SELECT SIMILARITY(title, 'Nation'), title FROM gallery WHERE title ...
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377 views

How to create an Access query to find # symbol into a field?

It seems easy but I'm missing something. I have a MySQL database that is connected from access through ODBC connector. I'm looking for the fields where there are # symbol but I'm getting zero ...
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How to create an Sql table from SELECT with a multiple row DISTINCT constraint?

I want to create a table from a SELECT statement based on a multiple row DISTINCT, but PostgreSQL does not allow me to do it. I need to create a table where the elements were previously selected from ...
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865 views

Retrieving a fixed range of rows from Postgresql

I have a query: select qid,ansid,ans from table1 where askerid='something' This query can retrieve many rows. But I want to display only 50 rows at a time and then if the user clicks on more, the ...
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221 views

MySQL: SELECT the n-th item from an ordered result

SELECTing the top n elements from a table is easy: SELECT id FROM pixels WHERE pixel_id='some_pixel_id' ORDER BY id DESC LIMIT 1000; Finding the n-th element with a subquery is quite ...
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82 views

Can you search using an index while indexes are being updated in oracle11g?

I am using oracle 11g. I noticed some performance problems that causes hanging on some search operations. Can I still search based on an index while that index is being updated in the database?
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I want a select to give me id's that are not in a consecutively order

I have an Oracle db with a table like this: +----+-------+ | ID | INDEX | +----+-------+ | 1 | 0 | | 1 | 1 | | 2 | 4 | | 2 | 5 | | 2 | 6 | | 3 | 0 | | 3 | 1 | | 3 ...
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34 views

MYSQL Select, where rows exists

I have a Mysql Database and tables with the structure: Table 'photos' - ID, Name Table 'photos_tags' - Key, Photo_ID, Tag My goal is to select all photos, which has one tag (it's not a problem) ...
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79 views

Grouping based on the status, then count its product and the total based on its category ID

I have a table with product ID, category ID and status of the product. +---------+-------------+-------------+ | id | cat_id | status | +---------+-------------+-------------+ | 1 ...
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32 views

Grant Select on some columns for specific user

I have a windows group with 20 people and all 20 people in the group were revoked access for some columns in the table. Now I need to add the select permissions for 2 of the users in this windows ...
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3answers
142 views

DISTINCT Role in SELECT

EDIT: @Moderators: Please delete this question. I still feel that it is unclear what I am asking. Maybe I could have used some Venn diagrams in order to describe the problem. The COUNTs do not seem to ...
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How to use relationships to extract data via select

Disclaimer: Novice in SQL I have 3 tables. There is one "major" table (labeled used_for_lookup below) used to do look-ups on and the other two (labeled fid_table and did_table below) are foreign keys ...
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Using count() and sum() in a calculation in a select

I am trying to do the following in a single select. We have a SAAS that has Company records and User records. A User is a member of a Company (Company.CompanyId = User.CompanyId). In the User record ...
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114 views

PostgreSQL SQL syntax - JOIN and substrings

I have a single table of hostnames and NFS exports, some but not all of which are related. Example entries: HOST VOLUME ----- ---------- host1 vol1 host1 vol2 host1 ...
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95 views

ORDER BY that doesn't contain repeating values

Relevant SQL Fiddle (postgres 9.2) How do I state a SELECT .. ORDER BY .. that avoids having repeated values for a column? That is, for rows of the column "rank" (1,3,3,1) how do I get a result so ...
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226 views

New field based on sum field

I'm trying to create a new field based in another (sum field) SELECT sum(price) AS old_price, old_price+100 AS total_price FROM sales This returns Unknown column 'old_price' in 'field list' sum ...
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104 views

performance difference between < and <=

I remember that there is a performance issue with SQLs that use "<" against "<=" because of statistics and/or histograms and/or the data itself, but I dont remember exactly the issue. I know ...