大约有 31,500 项符合查询结果（耗时：0.0175秒） [XML]
How do you find the row count for all your tables in Postgres
...
^[^|]*\|\s+([^|]*?)\s+\| table \|.*$
to:
select '\1', count(*) from \1 union/g
which will yield you something very similar to this:
select 'auth_group', count(*) from auth_group union
select 'auth_group_permissions', count(*) from auth_group_permissions union
select 'auth_permission', count(*...
Combine two ActiveRecord::Relation objects
...name_relation.merge(last_name_relation)
If you want to combine using OR (union), use or†:
first_name_relation.or(last_name_relation)
† Only in ActiveRecord 5+; for 4.2 install the where-or backport.
share
...
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 to define “type disjunction” (union types)?
...
Miles Sabin describes a very nice way to get union type in his recent blog post Unboxed union types in Scala via the Curry-Howard isomorphism:
He first defines negation of types as
type ¬[A] = A => Nothing
using De Morgan's law this allows him to define union ty...
Intersection and union of ArrayLists in Java
... Test().intersection(list1, list2));
System.out.println(new Test().union(list1, list2));
}
public <T> List<T> union(List<T> list1, List<T> list2) {
Set<T> set = new HashSet<T>();
set.addAll(list1);
set.addAll(list2);
...
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 is the strict aliasing rule?
...mited buffer doesn't necessarily help.
So how do I get around this?
Use a union. Most compilers support this without complaining about strict aliasing. This is allowed in C99 and explicitly allowed in C11.
union {
Msg msg;
unsigned int asBuffer[sizeof(Msg)/sizeof(unsigned int)];
};
...
Why do we need C Unions?
When should unions be used? Why do we need them?
18 Answers
18
...
How can I view live MySQL queries?
...wered Jul 31 '14 at 11:46
python1981python1981
4,20022 gold badges2323 silver badges4040 bronze badges
...