大约有 531 项符合查询结果（耗时：0.0181秒） [XML]
Is it possible to insert multiple rows at a time in an SQLite database?
...TO 'tablename'
SELECT 'data1' AS 'column1', 'data2' AS 'column2'
UNION ALL SELECT 'data1', 'data2'
UNION ALL SELECT 'data1', 'data2'
UNION ALL SELECT 'data1', 'data2'
a note on performance
I originally used this technique to efficiently load large datasets from Ruby on Rails. However, as...
MongoDB: Combine data from multiple collections into one..how?
...
Doing unions in MongoDB in a 'SQL UNION' fashion is possible using aggregations along with lookups, in a single query. Here is an example I have tested that works with MongoDB 4.0:
// Create employees data for testing the union.
d...
How can I get the intersection, union, and subset of arrays in Ruby?
...et operations on arrays by doing &(intersection), -(difference), and |(union).
Obviously I didn't implement the MultiSet to spec, but this should get you started:
class MultiSet
attr_accessor :set
def initialize(set)
@set = set
end
# intersection
def &(other)
@set & o...
Union of dict objects in Python [duplicate]
How do you calculate the union of two dict objects in Python, where a (key, value) pair is present in the result iff key is in either dict (unless there are duplicates)?
...
Does Python have an ordered set?
...list.
OrderedSet([1, 2, 3])
This is a MutableSet, so the signature for .union doesn't match that of set, but since it includes __or__ something similar can easily be added:
@staticmethod
def union(*sets):
union = OrderedSet()
union.union(*sets)
return union
def union(self, *sets):
...
How to get first and last day of previous month (with timestamp) in SQL Server
...st month' AS Title, CONVERT(VARCHAR, @FirstDayOfLastMonth , 120) AS [ODBC]
UNION
SELECT
'Last day of last month' AS Title, CONVERT(VARCHAR, @LastDayOfLastMonth , 120) AS [ODBC]
Run the above code to produce the following output:
Note: Bear in mind that today's date for me is 12th Septemb...
Set operations (union, intersection) on Swift array?
...ing> = Set(array2)
Swift 3.0+ can do operations on sets as:
firstSet.union(secondSet)// Union of two sets
firstSet.intersection(secondSet)// Intersection of two sets
firstSet.symmetricDifference(secondSet)// exclusiveOr
Swift 2.0 can calculate on array arguments:
set1.union(array2) //...
Turning a Comma Separated string into individual rows
... STUFF(String, 1, CHARINDEX(',', String + ','), '')
FROM Testdata
UNION all
SELECT
SomeID,
OtherID,
LEFT(String, CHARINDEX(',', String + ',') - 1),
STUFF(String, 1, CHARINDEX(',', String + ','), '')
FROM tmp
WHERE
String > ''
)
SELECT...
Efficiently convert rows to columns in sql server
...<| SQL_Code |>] = '' '' '
+ 'UNION ALL '
+ 'SELECT ''----------------------------------------------------------------------------------------------------'' '
+ 'UNION ALL '
...
What does |= (ior) do in Python?
...ace+ operation between pairs of objects. In particular, between:
sets: a union operation
dicts: an update operation
counters: a union (of multisets) operation
numbers: a bitwise OR, binary operation
In most cases, it is related to the | operator. See examples below.
Sets
For example, the union o...