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How to find gaps in sequential numbering in mysql?
... next_id, (b - a) -1 AS missing_inbetween
FROM
(
SELECT a1.id AS a , MIN(a2.id) AS b
FROM arrc_vouchers AS a1
LEFT JOIN arrc_vouchers AS a2 ON a2.id > a1.id
WHERE a1.id <= 100
GROUP BY a1.id
) AS tab
WHERE
b > a + 1
This will give you a table showing the id that has ids missing abov...
How do I perform the SQL Join equivalent in MongoDB?
...: 'orlando', last: 'becerra' },
age: 27
},
{
_id: 'a2',
name: { first: 'mayra', last: 'sanchez' },
age: 21
}
]);
.- Categories:
db.categories.insert([
{
_id: 'c1',
name: 'sci-fi'
},
{
_id: 'c2',
name: 'romance...
PHP function overloading
...tion(string '.$key.')', __function__);
// Get a reference
$a2 =& Overloadable::refAccess($key); // $a2 =& $GLOBALS['val'];
$a2 *= 3; // change the reference value
}
}
//----------------------------------------------------------
// Some data to work with:
$val ...
Return empty cell from formula in Excel
...elf annihilating formula. Put in cell, say B2, the following formula:
=IF(A2=0,GetTrueBlank,A2)
The above formula in B2 will evaluate to trueblank, if you type 0 in A2.
You can download a demonstration file here.
In the example above, evaluating formula to trueblank results in an empty cell. C...
How to use > in an xargs command?
...
Tudor Timi
6,68511 gold badge1616 silver badges4444 bronze badges
answered May 10 '09 at 18:59
Stephan202Stephan202
...
parseInt vs unary plus, when to use which?
...
sahil
3,11011 gold badge1616 silver badges3737 bronze badges
answered Jun 14 '13 at 10:46
JosephJoseph
...
Detect 7 inch and 10 inch tablet programmatically
...he liberty to fix that.
– Jonik
Dec 11 '13 at 9:46
21
...
Get top n records for each group of grouped results
...VALUES('Laura',2,39);
SELECT a.* FROM mytable AS a
LEFT JOIN mytable AS a2
ON a.groupname = a2.groupname AND a.age <= a2.age
GROUP BY a.person
HAVING COUNT(*) <= 2
ORDER BY a.groupname, a.age DESC;
gives me:
a.person a.groupname a.age
---------- ----------- ----------
Sha...
Logical operators for boolean indexing in Pandas
...; import numpy as np
>>> a1 = np.array([0, 0, 1, 1])
>>> a2 = np.array([0, 1, 0, 1])
>>> np.logical_and(a1, a2)
array([False, False, False, True])
>>> np.bitwise_and(a1, a2)
array([0, 0, 0, 1], dtype=int32)
And since NumPy (and similarly pandas) does different...
How to do an INNER JOIN on multiple columns
...
something like....
SELECT f.*
,a1.city as from
,a2.city as to
FROM flights f
INNER JOIN airports a1
ON f.fairport = a1. code
INNER JOIN airports a2
ON f.tairport = a2. code
share
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