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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Counting rows from a subquery

Simple: I would like to count the number of rows from the sub-query. Note that status is whether the host is online or not. Bad code SELECT COUNT(ip_address) FROM `ports` ( SELECT DISTINCT ...
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2answers
21 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 ...
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1answer
55 views

Multiple left join where not in another table

I have the following tables (there is more detailed data in each one, I just put the minimum to create a sample): __________ _____________ _____________ _____________ | person | | provider | | ...
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1answer
69 views

How to select users that doesn't in the role

I have 4 roles which are Admin, Procurement, Accounting, HR roles and 3 tables which are Users, Roles and Userroles. They user can have many roles as well as the roles can have many users. the problem ...
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3answers
345 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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1answer
52 views

select group by with multiple AND conditions on the same columns

I've an sql table like this: SID|SERVICE_SID|ATTRIBUTE_SID|VALUE 1 2 5 "VAL1" 2 2 4 "VAL8" 3 2 3 "VAL4" 4 11 5 ...
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1answer
163 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 ...
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2answers
497 views

How to find all schemas where a table has records?

In my Oracle database, I have a number of schemas (users/owners) with similar table structures (about 100 in total). However, some tables are empty in a lot of schemas. Is there a way to find out for ...
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1answer
51 views

Unexpected empty result [closed]

select a,b from table1 where a not in (select x as a from table2) AND b not in (select y as b from table3) The above query gives an empty result. Why? And how should I construct this combined ...
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46 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 ...
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1answer
2k views

Group by age range and gender with aggregation function on some columns

In Mysql, I have a patient table with id, birth_year and gender. Next table is transactions in which I have id, patient_id [FK from patient] and checkup_date. I need to select rows such that I get ...
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2answers
543 views

Multiple SELECT vs single SELECT over TCIP

My question is a performance one: I need to select roughly 400+ rows, i know their ids. currently i loop in code and fire off multiple queries over tcp/ip - because its easy: ... select [columns] ...
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1answer
305 views

How to calculate average of list of qualifications of each pupil MYSQL

I have this database and query: http://sqlfiddle.com/#!2/b4cf72/116 And I would like to add a column with the average of the exam qualifications. However, I try doing this but it tells me there are ...
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1answer
324 views

Need to optimize simple SELECT query for InnoDB table with 2million rows

I'd like to make this query the fastest possible, since it's called really often. SELECT login_events.id FROM login_events WHERE ( DATE(created_at) >= DATE(CURRENT_DATE) AND person_id = 1 ) ...
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1answer
10k views

Select records in one table but not in another, when the second table is not matching on primary key

I have two tables from which I need only the results that appear in one table (list) which do not appear in the second table (cardinal). The list table's primary key is sku, and the table has a ...
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1answer
2k views

Insert from one row to another using cases

My original table was(being used since 2005): CREATE TABLE `request` ( `msg` VARCHAR(150) NOT NULL, `id` VARCHAR(20) NOT NULL, `ctg` VARCHAR(10) NOT NULL DEFAULT 'misc', `date` ...
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1answer
269 views

MySQL SELECT query: i want show duplicated entries

Example My query is: SELECT code_CAT FROM categories WHERE id_code IN(14,14,14,14); output is: 53724 Only one row. Instead I want this output: 53724 53724 53724 53724 How can I achieve ...
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1answer
1k views

How to change the display of an empty string in mysql command line tool?

I'm maintaining a database with InnoDB tables. These tables have some columns of type (from show create table): `val0` varchar(30) default NULL, `val1` varchar(30) default NULL, etc... From the ...
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1answer
174 views

Complex mysql selection

I have the following table, id | booki_id | bet_id | bet | bettype | line | odds 1 | 123 | 321 | 1 | 3way | 0,0 | 2.3 2 | 123 | 321 | 2 | 3way | ...
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1answer
46 views

MySQL INSERT … SELECT Performance

I know that this query will lock table2: UPDATE table1... SELECT .. FROM table2 How about this query ? INSERT INTO table1... SELECT .. FROM table2 Does this query also create a lock on table2?
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28 views

Error 1052 Field is Ambiguous using Inner Join Function

Error '1052' Field is ambiguous. I understand the error that is happening, and I've looked at several places for the fix and then applied the inner join function in attempt to fix it. It's still not ...
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1answer
117 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 ...
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1answer
25 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 ...
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1answer
60 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, ...
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1answer
54 views

Recommended Database(s) for Selecting Random Rows

I'm familiar with selecting random rows from a table in PostgreSQL. It's really slow. I've looked into some other databases and they all seem to be bad at it. Mostly because it's not a normal use case ...
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94 views

Select data where column value exists in seperate rows for same reference id

This is on a MySQL database. Locations have services. What I want is to get all results where service_id is 2 AND 3, not OR so using IN is out I believe. Database ---------------------------- | ...
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4answers
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MSSQL Select all parent rows for which exists a combination of children rows with desired value

I would like to select all parent rows for which exists a combination of children rows with desired value. The easiest approach is to use multiple exists clauses, but this is not optimal - anyone ...
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1answer
288 views

Can I parse a text value from a specific column in a query (MySQL)?

I was playing around with Sakila and I ran across the actor_info view and one of its columns is film_info which is a detail of all the movies one actor has worked in. For example a query would be: ...
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1answer
4k views

MySQL Count rows from another table for each record in table

SELECT student.StudentID, student.`Name`, COUNT(attendance.AttendanceID) AS Total FROM student LEFT JOIN attendance ON student.StudentID = attendance.StudentID I am trying to count the last ...
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1answer
52 views

Creating a View with results from join of scalar tables

I am really bad at SQL Queries and seem to be stuck at a very odd problem. Maybe there's an alternative of doing this, but I simply can't figure it out. Maybe you guys can help! So, here's my ...
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2answers
173 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||'''' ...
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3answers
1k views

Select only rows with minimum values from union table

SQL Server 2005 Here is a sampling of the data from a union of two tables (named "vProducts_All"): DBID UPC Price1 Price2 1 023614025559 689.0000 649.0000 2 ...
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537 views

Select statement for selecting every week's log record

Here is a simplified version of the table in question: +------------------------------------------------------+ | DatabaseName | LogRecordNumber | LogTimestamp | ...
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470 views

Determine last time a mysql table was accessed (i.e. SELECT'ed)

In my mysql DB schema there are old tables that are no longer used. I want to come up with a systematic way to show my developer a list of tables and last time they were read (SELECT'ed, not ...
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1answer
42 views

Should I drop this column or is there a query that can achieve a results table without duplicate columns?

I use a column named active in several of my database tables to adjust whether a particular entry/row/user/etc should be included in future query result tables instead of deleting the information. ...
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1answer
436 views

Running queries directly on DB2 databases

Just have a general query, if it is really fine or safe to run long select queries on RDBMS production Databases specifically DB2? If NO, what are the major risks and issues in executing select ...
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1answer
471 views

Low-level relational operators from SQL

I have been asked to outline the sequence of commands using low-level operators (join/project/select) that are used in the following SQL statement; SELECT d.name, k.city FROM DOG d, KENNEL k WHERE ...
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1answer
1k views

How do I query for leaf nodes in a hierarchy using a closure table?

I have some hierarchical data (representing musical instruments and playing techniques), where each leaf in the hierarchy is an audio file. The nesting depth of leaf nodes will vary because some ...
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1answer
473 views

Slow running query with inner SELECT in where clause

I have a query that looks like the following: USE DATABASE3; GO SELECT t1.COL1 AS COLUMN1, t2.COL2 AS COLUMN2, t1.COL3, t1.COL4 AS COLUMN4, t1.COL5 AS COLUMN5, ...
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355 views

INSERT INTO selected columns creates new column from JOIN [closed]

I have an INSERT INTO ... SELECT.. query that uses a JOIN on two tables. The results of the query should take a subset of the information and insert it into an existing table. That part works, but the ...
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1answer
11k views

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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1answer
6k 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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1answer
496 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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1answer
324 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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1answer
397 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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1answer
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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3answers
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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1answer
324 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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2answers
35 views

SQLPLUS: SELECT INTO prompting for variable value

Any idea why this is prompting me for the value? I'm calling the script via batch file: DECLARE precount NUMBER; nowcount NUMBER; BEGIN SELECT COUNT(*) INTO precount FROM ...
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1answer
32 views

Is it possible to write a select * view that includes new columns added to table?

I would like to write a view that is essentially something simple select a + b, * from table_name and will always truly include all columns in table_name, even when I add or remove them. If I do the ...