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How do I check if a column is empty or null in MySQL?
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This will select all rows where some_col is NULL or '' (empty string)
SELECT * FROM table WHERE some_col IS NULL OR some_col = '';
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Function to Calculate Median in SQL Server
... in all cases. It also requires SQL 2012 or later.
DECLARE @c BIGINT = (SELECT COUNT(*) FROM dbo.EvenRows);
SELECT AVG(1.0 * val)
FROM (
SELECT val FROM dbo.EvenRows
ORDER BY val
OFFSET (@c - 1) / 2 ROWS
FETCH NEXT 1 + (1 - @c % 2) ROWS ONLY
) AS x;
Of course, just because o...
NOT IN vs NOT EXISTS
...llow NULLs the NOT IN will be treated identically to the following query.
SELECT ProductID,
ProductName
FROM Products p
WHERE NOT EXISTS (SELECT *
FROM [Order Details] od
WHERE p.ProductId = od.ProductId)
The exact plan may vary but for my examp...
Cannot truncate table because it is being referenced by a FOREIGN KEY constraint?
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IF OBJECT_ID('tempdb..#FKs') IS NOT NULL
DROP TABLE #FKs
-- GET FKs
SELECT ROW_NUMBER() OVER (ORDER BY OBJECT_NAME(parent_object_id), clm1.name) as ID,
OBJECT_NAME(constraint_object_id) as ConstraintName,
OBJECT_NAME(parent_object_id) as TableName,
clm1.name as ColumnName...
How to convert IPython notebooks to PDF and HTML?
...eps.
For HTML output, you should now use Jupyter in place of IPython and select File -> Download as -> HTML (.html) or run the following command:
jupyter nbconvert --to html notebook.ipynb
This will convert the Jupyter document file notebook.ipynb into the html output format.
Google C...
Should arrays be used in C++?
...only an issue for static
data, where something like:
struct Data { int i; char const* s; };
Data const ourData[] =
{
{ 1, "one" },
{ 2, "two" },
// ...
};
This is often preferable to using a vector (and std::string), since it
avoids all order of initialization issues; the data is pre...
How to drop a PostgreSQL database if there are active connections to it?
...Query pg_stat_activity and get the pid values you want to kill, then issue SELECT pg_terminate_backend(pid int) to them.
PostgreSQL 9.2 and above:
SELECT pg_terminate_backend(pg_stat_activity.pid)
FROM pg_stat_activity
WHERE pg_stat_activity.datname = 'TARGET_DB' -- ← change this to your DB
AN...
VB.NET equivalent to C# var keyword [duplicate]
...hen just use the Dim keyword, thus:
Dim query = From x In y Where x.z = w Select x
Contrary to some of the other answers, you do not need Option Strict On.
If you're using the VS IDE you can just hover over the variable names, but to get the compile-time types of variables (GetType(variableName)...
Search of table names
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I'm using this and works fine
SELECT * FROM INFORMATION_SCHEMA.TABLES
WHERE TABLE_NAME LIKE '%%'
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How to keep the spaces at the end and/or at the beginning of a String?
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@androiddeveloper, \u indicates a unicode character as an escape sequence (not a unicode char directly in the file). &#nnn; indicates an html entity, which means that you're relying on your xml string being html parsed (it is by default when used in text views)....