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Truncating all tables in a Postgres database
...e IN VARCHAR) RETURNS void AS $$
DECLARE
statements CURSOR FOR
SELECT tablename FROM pg_tables
WHERE tableowner = username AND schemaname = 'public';
BEGIN
FOR stmt IN statements LOOP
EXECUTE 'TRUNCATE TABLE ' || quote_ident(stmt.tablename) || ' CASCADE;';
END LOO...
LINQ: Select an object and change some properties without creating a new object
.... But here is the expanded LINQ expression example.
var query = someList.Select(x => { x.SomeProp = "foo"; return x; })
What this does is use an anonymous method vs and expression. This allows you to use several statements in one lambda. So you can combine the two operations of setting the ...
How to pass an array into a SQL Server stored procedure
...WithEmployees
@List AS dbo.IDList READONLY
AS
BEGIN
SET NOCOUNT ON;
SELECT ID FROM @List;
END
GO
Now in your C# code:
// Obtain your list of ids to send, this is just an example call to a helper utility function
int[] employeeIds = GetEmployeeIds();
DataTable tvp = new DataTable();
tvp.C...
MySQL JOIN the most recent row only?
...
You may want to try the following:
SELECT CONCAT(title, ' ', forename, ' ', surname) AS name
FROM customer c
JOIN (
SELECT MAX(id) max_id, customer_id
FROM customer_data
GROUP BY customer_id
...
How to fix “no valid 'aps-environment' entitlement string found for application” in Xcode 4.3?
...rrect in the build settings.
You need to make sure the correct profile is selected for the "Debug" configuration, and to be safe, that you have selected the correct profile for both the "Debug" and child-node labelled "Any iOS SDK":
Although this screenshot shows the "Automatic Developer" profil...
Open directory dialog
I want the user to select a directory where a file that I will then generate will be saved. I know that in WPF I should use the OpenFileDialog from Win32, but unfortunately the dialog requires file(s) to be selected - it stays open if I simply click OK without choosing one. I could "hack up" the f...
UITableView didSelectRowAtIndexPath: not being called on first tap
I'm having an issue with UITableView's didSelectRowAtIndexPath .
16 Answers
16
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What makes a SQL statement sargable?
...non-sargable is to include a field inside a function in the where clause:
SELECT ... FROM ...
WHERE Year(myDate) = 2008
The SQL optimizer can't use an index on myDate, even if one exists. It will literally have to evaluate this function for every row of the table. Much better to use:
WHERE myDat...
SQL SERVER: Get total days between two dates
...:09.3312722';
DECLARE @enddate datetime2 = '2009-05-04 12:10:09.3312722';
SELECT DATEDIFF(day, @startdate, @enddate);
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Get table column names in MySQL?
...DESCRIBE my_table;
Or in newer versions you can use INFORMATION_SCHEMA:
SELECT COLUMN_NAME
FROM INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_SCHEMA = 'my_database' AND TABLE_NAME = 'my_table';
Or you can use SHOW COLUMNS:
SHOW COLUMNS FROM my_table;
...