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SQL JOIN vs IN performance?
...king, IN and JOIN are different queries that can yield different results.
SELECT a.*
FROM a
JOIN b
ON a.col = b.col
is not the same as
SELECT a.*
FROM a
WHERE col IN
(
SELECT col
FROM b
)
, unless b.col is unique.
However, this is the syno...
How to drop all user tables?
...
BEGIN
FOR cur_rec IN (SELECT object_name, object_type
FROM user_objects
WHERE object_type IN
('TABLE',
'VIEW',
'MATERIAL...
SQL - HAVING vs. WHERE
...ows; HAVING clause introduces a condition on aggregations, i.e. results of selection where a single result, such as count, average, min, max, or sum, has been produced from multiple rows. Your query calls for a second kind of condition (i.e. a condition on an aggregation) hence HAVING works correctl...
Query to list all stored procedures
...e not in the master database, system stored procedures won't be returned.
SELECT *
FROM DatabaseName.INFORMATION_SCHEMA.ROUTINES
WHERE ROUTINE_TYPE = 'PROCEDURE'
If for some reason you had non-system stored procedures in the master database, you could use the query (this will filter out MOST ...
Find method references in Xcode
...
Select the method you're interested in, or position the text cursor within it.
Open the "Related Files" menu via the icon at the top-left of the Editor. (It's the button immediately to the left of the back button).
Go to the ...
How to check if field is null or empty in MySQL?
...
Either use
SELECT IF(field1 IS NULL or field1 = '', 'empty', field1) as field1
from tablename
or
SELECT case when field1 IS NULL or field1 = ''
then 'empty'
else field1
end as field1
from tablename
...
Select a Dictionary with LINQ
I have used the "select" keyword and extension method to return an IEnumerable<T> with LINQ, but I have a need to return a generic Dictionary<T1, T2> and can't figure it out. The example I learned this from used something in a form similar to the following:
...
How to exclude particular class name in CSS selector?
...
One way is to use the multiple class selector (no space as that is the descendant selector):
.reMode_hover:not(.reMode_selected):hover
{
background-color: #f0ac00;
}
<a href="" title="Design" class="reMode_design reMode_hover">
<span&...
In Vim/Vi, how do you move the cursor to the end of the previous word?
...you'll go to the end of the previous, while be you need to be on the first char of the initial word.
– TankorSmash
Dec 4 '13 at 4:06
14
...
Set selected index of an Android RadioGroup
Is there a way to set the selected index of a RadioGroup in android, other than looping through the child radiobuttons and selecting checking the radio button at the selected index?
...