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MySQL ON DUPLICATE KEY - last insert id?
...on to that MySQL function.
From the MySQL documentation example:
If a table contains an AUTO_INCREMENT column and INSERT ... UPDATE inserts a row, the LAST_INSERT_ID() function returns the AUTO_INCREMENT value. If the statement updates a row instead, LAST_INSERT_ID() is not meaningful. However,...
When should I use a composite index?
For example, I have a homes table:
9 Answers
9
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mysql -> insert into tbl (select from another table) and some default values [duplicate]
As the title says, I am trying to insert into one table selecting values from another table and some default values.
5 Ans...
How to select records from last 24 hours using SQL?
...
SELECT *
FROM table_name
WHERE table_name.the_date > DATE_SUB(CURDATE(), INTERVAL 1 DAY)
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Using R to download zipped data file, extract, and import data
...oad.file("http://www.newcl.org/data/zipfiles/a1.zip",temp)
data <- read.table(unz(temp, "a1.dat"))
unlink(temp)
Compressed (.z) or gzipped (.gz) or bzip2ed (.bz2) files are just the file and those you can read directly from a connection. So get the data provider to use that instead :)
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Data structure: insert, remove, contains, get random element, all at O(1)
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Consider a data structure composed of a hashtable H and an array A. The hashtable keys are the elements in the data structure, and the values are their positions in the array.
insert(value): append the value to array and let i be its index in A. Set H[value]=i.
remov...
T-SQL split string
...CTION dbo.splitstring ( @stringToSplit VARCHAR(MAX) )
RETURNS
@returnList TABLE ([Name] [nvarchar] (500))
AS
BEGIN
DECLARE @name NVARCHAR(255)
DECLARE @pos INT
WHILE CHARINDEX(',', @stringToSplit) > 0
BEGIN
SELECT @pos = CHARINDEX(',', @stringToSplit)
SELECT @name = SUBSTRING(@strin...
SQL Server - SELECT FROM stored procedure
...ure can return multiple result sets, each with its own schema. It's not suitable for using in a SELECT statement.
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Cannot resolve the collation conflict between “SQL_Latin1_General_CP1_CI_AS” and “Latin1_General_CI_
...
You have a mismatch of two different collations in your table. You can check what collations each column in your table(s) has by using this query:
SELECT
col.name, col.collation_name
FROM
sys.columns col
WHERE
object_id = OBJECT_ID('YourTableName')
Collations are n...
SQL to find the number of distinct values in a column
...aggregate function:
SELECT COUNT(DISTINCT column_name) AS some_alias FROM table_name
This will count only the distinct values for that column.
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