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What does SQL clause “GROUP BY 1” mean?
...
SELECT account_id, open_emp_id
^^^^ ^^^^
1 2
FROM account
GROUP BY 1;
In above query GROUP BY 1 refers to the first column in select statement which is
account_id.
You also can speci...
What is the use of the square brackets [] in sql statements?
...
sql also uses square brackets in the like-operator of a select query to limit results using regular expressions. codeproject.com/Articles/33941/SQL-LIKE-Operator
– Jens Frandsen
Sep 4 '13 at 18:49
...
T-SQL query to show table definition?
...n get most of the details from Information Schema Views and System Views.
SELECT ORDINAL_POSITION, COLUMN_NAME, DATA_TYPE, CHARACTER_MAXIMUM_LENGTH
, IS_NULLABLE
FROM INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_NAME = 'Customers'
SELECT CONSTRAINT_NAME
FROM INFORMATION_SCHEMA.CONSTRAINT_TABLE_US...
Dynamically select data frame columns using $ and a character value
...and some variable names stored in a character vector cols . When I try to select a variable from mtcars using a dynamic subset of cols , nether of these work
...
Possible to perform cross-database queries with PostgreSQL?
... executes a query in a remote database
dblink executes a query (usually a SELECT, but it can be any SQL
statement that returns rows) in a remote database.
When two text arguments are given, the first one is first looked up as
a persistent connection's name; if found, the command is executed on
that...
How do I copy to the clipboard in JavaScript?
...
document.body.appendChild(textArea);
textArea.focus();
textArea.select();
try {
var successful = document.execCommand('copy');
var msg = successful ? 'successful' : 'unsuccessful';
console.log('Fallback: Copying text command was ' + msg);
} catch (err) {
consol...
How do I select text nodes with jQuery?
...ext nodes with the accepted filter function. If you're only interested in selecting text nodes that contain non-whitespace, try adding a nodeValue conditional to your filter function, like a simple $.trim(this.nodevalue) !== '':
$('element')
.contents()
.filter(function(){
return t...
How to split the name string in mysql?
...ast names. The middle name will show as NULL if there is no middle name.
SELECT
SUBSTRING_INDEX(SUBSTRING_INDEX(fullname, ' ', 1), ' ', -1) AS first_name,
If( length(fullname) - length(replace(fullname, ' ', ''))>1,
SUBSTRING_INDEX(SUBSTRING_INDEX(fullname, ' ', 2), ' ', -1) ,NU...
SQL UPDATE SET one column to be equal to a value in a related table referenced by a different column
...result set to update is before running the update (same query, just with a select):
select *
from QuestionTrackings q
inner join QuestionAnswers a
on q.AnswerID = a.AnswerID
where q.QuestionID is null -- and other conditions you might want
Particularly whether each answer id has definitely only 1...
Hidden Features of Xcode 4
... View > Utilities > Code Snippet Library. To add a new code snippet, select some text in the editor view and drag it into the snippet library. You can either drag a snippet out and drop it in your code to use it, or, much more conveniently, assign a completion shortcut to it.
When you type i...