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Fastest way to count exact number of rows in a very large table?
I have come across articles that state that SELECT COUNT(*) FROM TABLE_NAME will be slow when the table has lots of rows and lots of columns.
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Clone private git repo with dockerfile
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The answer selected for this question is not a good answer anymore. It was correct in 2014 but for 2020 this is the correct answer.
– Bikal Basnet
Apr 8 at 19:05
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Two versions of python on linux. how to make 2.7 the default
...n in /usr/bin, and may have scripts that depend on this being present, and selected by #! /usr/bin/env python. You can usually get away with running Python 2.6 scripts in 2.7, but do you want to risk it?
On top of that, monkeying with /usr/bin can break your package manager's ability to manage pack...
PostgreSQL create table if not exists
..._mytable()
RETURNS void
LANGUAGE plpgsql AS
$func$
BEGIN
IF EXISTS (SELECT FROM pg_catalog.pg_tables
WHERE schemaname = 'myschema'
AND tablename = 'mytable') THEN
RAISE NOTICE 'Table myschema.mytable already exists.';
ELSE
CREATE TABLE myschema...
Adding multiple columns AFTER a specific column in MySQL
...ermitted in a single ALTER TABLE statement, separated by commas. This is a MySQL extension to standard SQL, which permits only one of each clause per ALTER TABLE statement.
– informatik01
May 1 '19 at 13:21
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'Microsoft.ACE.OLEDB.12.0' provider is not registered on the local machine
...bit shell:
(New-Object system.data.oledb.oledbenumerator).GetElements() | select SOURCES_NAME, SOURCES_DESCRIPTION
and you will see which provider your system can use
the long story:
the strings can be found with http://live.sysinternals.com/strings.exe
eg. on a 64bit System with 32bit drivers...
Delete all local changesets and revert to tree
... get out of a (small) mess is to first update to the latest revision, then select your changesets and initiate "merge with local". When the merge dialogue appears, simply click the little '+' icon to reveal some extra options, one of which is "discard changesets from merge target (other) revision". ...
What is a stored procedure?
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CREATE PROCEDURE Users_GetUserInfo
@login nvarchar(30)=null
AS
SELECT * from [Users]
WHERE ISNULL(@login,login)=login
A benefit of stored procedures is that you can centralize data access logic into a single place that is then easy for DBA's to optimize. Stored procedures also have...
Build project into a JAR automatically in Eclipse
...con on build.xml.
Step 2
Right-click on the root node in the project.
- Select Properties
- Select Builders
- Select New
- Select Ant Build
- In the Main tab, complete the path to the build.xml file in the bin folder.
Check the Output
The Eclipse output window (named Console) should show...
How do I pre-populate a jQuery Datepicker textbox with today's date?
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$(".selector").datepicker().datepicker("setDate", new Date()); will work and doesn't make jQuery search the DOM twice.
– abc123
Aug 1 '13 at 20:36
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