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What are the differences between a clustered and a non-clustered index?
...than a clustered index
Both types of index will improve performance when select data with fields that use the index but will slow down update and insert operations.
Because of the slower insert and update clustered indexes should be set on a field that is normally incremental ie Id or Timestamp.
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MySQL string replace
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Yes, MySQL has a REPLACE() function:
mysql> SELECT REPLACE('www.mysql.com', 'w', 'Ww');
-> 'WwWwWw.mysql.com'
http://dev.mysql.com/doc/refman/5.0/en/string-functions.html#function_replace
Note that it's easier if you make that an alias when using SELECT
SEL...
How do I limit task tags to current project in Eclipse?
...gure the scope.
Down arrow at the top right -> Configure Contents:
Select a configuration on the left (or create a new one) and on the right in the Scope section select "On any element in same project".
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add column to mysql table if it does not exist
...rade_database_1_0_to_2_0()
BEGIN
-- rename a table safely
IF NOT EXISTS( (SELECT * FROM information_schema.COLUMNS WHERE TABLE_SCHEMA=DATABASE()
AND TABLE_NAME='my_old_table_name') ) THEN
RENAME TABLE
my_old_table_name TO my_new_table_name,
END IF;
-- add a column safely
IF NO...
How to make a select with array contains value clause in psql
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Try
SELECT * FROM table WHERE arr @> ARRAY['s']::varchar[]
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jQuery selector regular expressions
...d or regular expressions (not sure on the exact terminology) with a jQuery selector.
10 Answers
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SQL Server Management Studio, how to get execution time down to milliseconds
...able in your proc:
DECLARE @EndTime datetime
DECLARE @StartTime datetime
SELECT @StartTime=GETDATE()
-- Write Your Query
SELECT @EndTime=GETDATE()
--This will return execution time of your query
SELECT DATEDIFF(ms,@StartTime,@EndTime) AS [Duration in millisecs]
AND see this
Measuring Quer...
Return 0 if field is null in MySQL
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Would that be IFNULL((SELECT SUM(uop.price * uop.qty) FROM uc_order_products uop WHERE uo.order_id = uop.order_id) AS products_subtotal, 0)?
– Kevin
Oct 22 '10 at 13:46
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Reset auto increment counter in postgres
... Does anyone know why ALTER SEQUENCE product_id_seq RESTART WITH (SELECT MAX(id) from product); Doesn't work? The only way I found is to use two separate queries.
– Chris Huang-Leaver
Dec 20 '18 at 3:14
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Is there a better Windows Console Window? [closed]
... the system, or copied to a folder of the program (ttf, otf, fon, bdf)
Run selected tabs as Administrator (Vista+) or as selected user
Windows 7 Jump lists and Progress on taskbar
Integration with DosBox (useful in 64bit systems to run DOS applications)
Smooth resize, maximized and fullscreen window...