Questions tagged [sql]
Structured Query Language (SQL) is a language for querying databases. Questions should include code examples, table structure, sample data, and a tag for the DBMS implementation (e.g. MySQL, PostgreSQL, Oracle, MS SQL Server, IBM DB2, etc.) being used. If your question relates solely to a specific DBMS (uses specific extensions/features), use that DBMS's tag instead. Answers to questions tagged with SQL should use ISO/IEC standard SQL.
624,823
questions
1664votes
27answers
3.0mviews
Insert into ... values ( SELECT ... FROM ... )
I am trying to INSERT INTO a table using the input from another table. Although this is entirely feasible for many database engines, I always seem to struggle to remember the correct syntax for the ...
- 38.1k
1655votes
41answers
471kviews
Table Naming Dilemma: Singular vs. Plural Names [closed]
Academia has it that table names should be the singular of the entity that they store attributes of.
I dislike any T-SQL that requires square brackets around names, but I have renamed a Users table ...
1582votes
22answers
1.5mviews
What is the difference between UNION and UNION ALL?
What is the difference between UNION and UNION ALL?
- 51.1k
1575votes
16answers
1.8mviews
How can I delete using INNER JOIN with SQL Server?
I want to delete using INNER JOIN in SQL Server 2008.
But I get this error:
Msg 156, Level 15, State 1, Line 15
Incorrect syntax near the keyword 'INNER'.
My code:
DELETE
FROM WorkRecord2
INNER ...
- 16.3k
1507votes
33answers
3.0mviews
Find all tables containing column with specified name - MS SQL Server
Is it possible to query for table names which contain columns being
LIKE '%myName%'
?
- 26.3k
1501votes
27answers
1.7mviews
SQL select only rows with max value on a column [duplicate]
I have this table for documents (simplified version here):
id
rev
content
1
1
...
2
1
...
1
2
...
1
3
...
How do I select one row per id and only the greatest rev?
With the above data, the ...
- 27.6k
1494votes
7answers
299kviews
What are the options for storing hierarchical data in a relational database?
Good Overviews
Generally speaking, you're making a decision between fast read times (for example, nested set) or fast write times (adjacency list). Usually, you end up with a combination of the ...
1484votes
16answers
1.8mviews
How can I do an UPDATE statement with JOIN in SQL Server?
I need to update this table in SQL Server with data from its 'parent' table, see below:
Table: sale
id (int)
udid (int)
assid (int)
Table: ud
id (int)
assid (int)
sale.assid contains the ...
- 18.8k
1476votes
24answers
1.5mviews
How to reset AUTO_INCREMENT in MySQL
How can I reset the AUTO_INCREMENT of a field?
I want it to start counting from 1 again.
- 18.3k
1393votes
15answers
796kviews
Can I concatenate multiple MySQL rows into one field?
Using MySQL, I can do something like:
SELECT hobbies FROM peoples_hobbies WHERE person_id = 5;
My Output:
shopping
fishing
coding
but instead I just want 1 row, 1 col:
Expected Output:
shopping, ...
- 30.4k
1342votes
3answers
1.7mviews
Using group by on multiple columns
I understand the point of GROUP BY x.
But how does GROUP BY x, y work, and what does it mean?
- 52.6k
1298votes
17answers
1.1mviews
How can I list the tables in a SQLite database file that was opened with ATTACH?
What SQL can be used to list the tables, and the rows within those tables in an SQLite database file - once I have attached it with the ATTACH command on the SQLite 3 command line tool?
- 47.5k
1285votes
14answers
1.1mviews
SQL Server - Best way to get identity of inserted row?
What is the best way to get IDENTITY of inserted row?
I know about @@IDENTITY and IDENT_CURRENT and SCOPE_IDENTITY but don't understand the pros and cons attached to each.
Can someone please explain ...
- 475k
1243votes
6answers
767kviews
Difference between JOIN and INNER JOIN
Both these joins will give me the same results:
SELECT * FROM table JOIN otherTable ON table.ID = otherTable.FK
vs
SELECT * FROM table INNER JOIN otherTable ON table.ID = otherTable.FK
Is there ...
- 156k
1208votes
14answers
1.9mviews
How do I limit the number of rows returned by an Oracle query after ordering?
Is there a way to make an Oracle query behave like it contains a MySQL limit clause?
In MySQL, I can do this:
select *
from sometable
order by name
limit 20,10
to get the 21st to the 30th rows (skip ...
- 14.6k