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Computed / calculated / virtual / derived columns in PostgreSQL
Does PostgreSQL support computed / calculated columns, like MS SQL Server? I can't find anything in the docs, but as this feature is included in many other DBMSs I thought I might be missing something.
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sqlite3.ProgrammingError: Incorrect number of bindings supplied. The current statement uses 1, and t
... is also not recommended for security concerns - docs.python.org/3/library/sqlite3.html
– wesinat0r
Jul 6 at 14:57
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C# Lambda expressions: Why should I use them?
...erted to expression trees which allows for a lot of the magic like LINQ to SQL.
The following is an example of a LINQ to Objects expression using anonymous delegates then lambda expressions to show how much easier on the eye they are:
// anonymous delegate
var evens = Enumerable
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Difference between CLOB and BLOB from DB2 and Oracle Perspective?
... DB2: http://pic.dhe.ibm.com/infocenter/db2luw/v10r5/topic/com.ibm.db2.luw.sql.ref.doc/doc/r0008473.html
SQL and XML limits: http://pic.dhe.ibm.com/infocenter/db2luw/v10r5/topic/com.ibm.db2.luw.sql.ref.doc/doc/r0001029.html
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PostgreSQL delete with inner join
i am getting the following error PostgreSQL 8.2.11
5 Answers
5
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How accurately should I store latitude and longitude?
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If you're using SQL Server... It's worth noting that a precision of 1-9 uses 5 bytes. So you may was well use a decimal(9,6) instead of decimal(7,4) and take advantage of the higher accuracy since they both occupy the same amount of space.
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SQLite select where empty?
In SQLite, how can I select records where some_column is empty?
Empty counts as both NULL and "".
4 Answers
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Using psql how do I list extensions installed in a database?
...st all extensions that are already installed in a database or schema from psql?
3 Answers
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Django - filtering on foreign key properties
...the type of comparison used in the query that the django ORM produces, the sql will probably look like LIKE '%Foo%'.
– orangecaterpillar
Apr 7 at 0:43
add a comment
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Postgresql aggregate array
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Use array_agg: http://www.sqlfiddle.com/#!1/5099e/1
SELECT s.name, array_agg(g.Mark) as marks
FROM student s
LEFT JOIN Grade g ON g.Student_id = s.Id
GROUP BY s.Id
By the way, if you are using Postgres 9.1, you don't need to repeat the col...