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PostgreSQL: How to make “case-insensitive” query
Is there any way to write case-insensitive queries in PostgreSQL, E.g. I want that following 3 queries return same result.
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Should I commit or rollback a read transaction?
...mization points for your app. If you're really curious, you can find the mySQL transaction handling code at bazaar.launchpad.net/~mysql/mysql-server/mysql-6.0/annotate/…
– Mark Brackett
May 21 '10 at 15:05
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Getting “Lock wait timeout exceeded; try restarting transaction” even though I'm not using a transac
I'm running the following MySQL UPDATE statement:
17 Answers
17
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Random record in ActiveRecord
... for 100 randomly selected entries. (Be aware that it's RANDOM() in PostgreSQL and RAND() in MySQL ... not as portable as you may want it to be.)
– Florian Pilz
Jun 16 '11 at 13:17
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Use LINQ to get items in one List, that are not in another List
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Bit late to the party but a good solution which is also Linq to SQL compatible is:
List<string> list1 = new List<string>() { "1", "2", "3" };
List<string> list2 = new List<string>() { "2", "4" };
List<string> inList1ButNotList2 = (from o in list1
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How to concatenate strings of a string field in a PostgreSQL 'group by' query?
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PostgreSQL 9.0 or later:
Recent versions of Postgres (since late 2010) have the string_agg(expression, delimiter) function which will do exactly what the question asked for, even letting you specify the delimiter string:
SELECT co...
PostgreSQL Autoincrement
I'm switching from MySQL to PostgreSQL and was wondering how I can do autoincrement values. I saw in the PostgreSQL docs a datatype "serial", but I get syntax errors when using it (in v8.0).
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Quickly reading very large tables as dataframes
...ata is passed to and from R in a binary format, which is faster.) read.csv.sql in the sqldf package, as described in JD Long's answer, imports data into a temporary SQLite database and then reads it into R. See also: the RODBC package, and the reverse depends section of the DBI package page. MonetD...
How to check if a table exists in a given schema
...tion in a function. Example:
Check if sequence exists in Postgres (plpgsql)
A query like above avoids possible exceptions and is therefore slightly faster.
to_regclass(rel_name) in Postgres 9.4+
Much simpler now:
SELECT to_regclass('schema_name.table_name');
Same as the cast, but it retur...
Howto: Clean a mysql InnoDB storage engine?
Is it possible to clean a mysql innodb storage engine so it is not storing data from deleted tables?
2 Answers
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