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grep a tab in UNIX
...le '\t' , literal TABs (i.e. the ones that look like whitespace) are often converted to SPC when copypasting ...
– plijnzaad
Mar 7 '17 at 11:39
...
Java code for getting current time [duplicate]
...a.time
ZonedDateTime zdt = ZonedDateTime.now();
If needed for old code, convert to java.util.Date. Go through at Instant which is a moment on the timeline in UTC.
java.util.Date date = java.util.Date.from( zdt.toInstant() );
Time Zone
Better to specify explicitly your desired/expected time zo...
Anyway to prevent the Blue highlighting of elements in Chrome when clicking quickly?
...
In addition to the link provided by Floremin, which clears text selection using JavaScript to "clear" the selection, you can also use pure CSS to accomplish this. The CSS is here...
.noSelect {
-webkit-touch-callout: none;
-webkit-user-select: none;
-khtml-user-select: none;
...
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...
How to select only the first rows for each unique value of a column
...
A very simple answer if you say you don't care which address is used.
SELECT
CName, MIN(AddressLine)
FROM
MyTable
GROUP BY
CName
If you want the first according to, say, an "inserted" column then it's a different query
SELECT
M.CName, M.AddressLine,
FROM
(
SELECT
...
Remove Select arrow on IE
I have select element, i want to remove the arrow, then i can add other icon..
i can do that for Firefox Safari and Chrome,
but this didn't work on IE9 .
...
Finding duplicate values in a SQL table
...
SELECT
name, email, COUNT(*)
FROM
users
GROUP BY
name, email
HAVING
COUNT(*) > 1
Simply group on both of the columns.
Note: the older ANSI standard is to have all non-aggregated columns in the GROUP BY ...
Escaping ampersand in URL
... must be percent-encoded. Percent-encoding
a reserved character involves converting the character to its
corresponding byte value in ASCII and then representing that value as
a pair of hexadecimal digits. The digits, preceded by a percent sign
("%") which is used as an escape character, are ...
How to create a MySQL hierarchical recursive query
... or self-joins.
MySQL 8+
with recursive cte (id, name, parent_id) as (
select id,
name,
parent_id
from products
where parent_id = 19
union all
select p.id,
p.name,
p.parent_id
from products p
inner join cte
...
Select rows which are not present in other table
...task, all of them standard SQL.
NOT EXISTS
Often fastest in Postgres.
SELECT ip
FROM login_log l
WHERE NOT EXISTS (
SELECT -- SELECT list mostly irrelevant; can just be empty in Postgres
FROM ip_location
WHERE ip = l.ip
);
Also consider:
What is easier to read in EXISTS...