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Counting DISTINCT over multiple columns
...ce, you could try creating a persisted computed column on either a hash or concatenated value of the two columns.
Once it is persisted, provided the column is deterministic and you are using "sane" database settings, it can be indexed and / or statistics can be created on it.
I believe a distinc...
Drop all tables whose names begin with a certain string
...
MYSQL: SELECT concat('DROP TABLE ',TABLE_NAME,";") as data FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_NAME LIKE '[prefix]%' --- for those who like me found this thread
– Andre
Nov 6 '12 at 0:27
...
How do I join two lists in Java?
...
In Java 8:
List<String> newList = Stream.concat(listOne.stream(), listTwo.stream())
.collect(Collectors.toList());
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Why is extending native objects a bad practice?
... at all:
// new types
const AddMonoid = {
empty: () => 0,
concat: (x, y) => x + y,
};
const ArrayMonoid = {
empty: () => [],
concat: (acc, x) => acc.concat(x),
};
const ArrayFold = {
reduce: xs => xs.reduce(
type(xs[0]).monoid.concat,
type(xs[0])...
Prepend a level to a pandas MultiIndex
...
A nice way to do this in one line using pandas.concat():
import pandas as pd
pd.concat([df], keys=['Foo'], names=['Firstlevel'])
An even shorter way:
pd.concat({'Foo': df}, names=['Firstlevel'])
This can be generalized to many data frames, see the docs.
...
Entity Attribute Value Database vs. strict Relational Model Ecommerce
...ntity.parent_id AS order_id,
sales_order_entity.entity_id,
CONCAT(CONCAT(UCASE(MID(sales_order_entity_varchar.value,1,1)),MID(sales_order_entity_varchar.value,2)), "Address") as type,
GROUP_CONCAT(
CONCAT( eav_attribute.attribute_code," ::::: ", sales_order_entity_v...
How can you determine how much disk space a particular MySQL table is taking up?
...eneric query where the maximum unit display is TB (TeraBytes)
SELECT
CONCAT(FORMAT(DAT/POWER(1024,pw1),2),' ',SUBSTR(units,pw1*2+1,2)) DATSIZE,
CONCAT(FORMAT(NDX/POWER(1024,pw2),2),' ',SUBSTR(units,pw2*2+1,2)) NDXSIZE,
CONCAT(FORMAT(TBL/POWER(1024,pw3),2),' ',SUBSTR(units,pw3*2+1,2)) T...
LINQ - Full Outer Join
...e the second query to exclude anything that was included in the first, use Concat instead. This is the SQL difference between UNION and UNION ALL
– cadrell0
Mar 30 '11 at 20:01
3
...
How to use GROUP BY to concatenate strings in SQL Server?
...r Vnext, SQL Azure you can use string_agg as below:
select id, string_agg(concat(name, ':', [value]), ', ')
from #YourTable
group by id
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PHP method chaining?
... }
return new static;
}
public static function concate($delimiter)
{
self::$delimiter = $delimiter;
foreach (self::$data as $d)
{
self::$result .= $d.$delimiter;
}
return new static;
}
public static function...