大约有 531 项符合查询结果（耗时：0.0217秒） [XML]
PreparedStatement IN clause alternatives?
...olumn FROM my_table WHERE search_column = ?, execute it for each value and UNION the results client-side. Requires only one prepared statement. Slow and painful.
Prepare SELECT my_column FROM my_table WHERE search_column IN (?,?,?) and execute it. Requires one prepared statement per size-of-IN-list....
Oracle PL/SQL - How to create a simple array variable?
...
BULK COLLECT INTO arrayvalues
FROM (select 'Matt' m_value from dual union all
select 'Joanne' from dual union all
select 'Robert' from dual
)
;
--
FOR i IN 1 .. arrayvalues.COUNT
LOOP
dbms_output.put_line(arrayvalues(i)||' is my friend');
END LO...
Is there a REAL performance difference between INT and VARCHAR primary keys?
...ue. One of my biggest databases has entries for Yugoslavia and the Soviet Union. I'm glad they're not primary keys.
– Paul Tomblin
Dec 1 '08 at 21:39
8
...
What is the fastest/most efficient way to find the highest set bit (msb) in an integer in C?
...zeof(uint32_t));
return (tmp>>20)-1023;
Or in C99 and later, use a union {double d; uint32_t u[2];};. But note that in C++, union type punning is only supported on some compilers as an extension, not in ISO C++.
This will usually be slower than a platform-specific intrinsic for a leading...
What is the Difference Between Mercurial and Git?
...can merge with an unrelated repository by doing:
git fetch <project-to-union-merge>
GIT_INDEX_FILE=.git/tmp-index git-read-tree FETCH_HEAD
GIT_INDEX_FILE=.git/tmp-index git-checkout-cache -a -u
git-update-cache --add -- (GIT_INDEX_FILE=.git/tmp-index git-ls-files)
cp .git/FETCH_HEAD .git/MERG...
SQL Server indexes - ascending or descending, what difference does it make?
...ts(db_id(), object_id('T1'), 1, NULL, 'DETAILED')
WHERE index_level = 0
UNION ALL
SELECT object_name(object_id) AS name,
page_count,
avg_fragmentation_in_percent,
fragment_count,
avg_fragment_size_in_pages
FROM
sys.dm_db_index_physical_stats(db_id(), object_id('...
Splitting string into multiple rows in Oracle
... select 108 Name, 'test' Project, 'Err1, Err2, Err3' Error from dual
union all
select 109, 'test2', 'Err1' from dual
)
select distinct
t.name, t.project,
trim(regexp_substr(t.error, '[^,]+', 1, levels.column_value)) as error
from
temp t,
table(cast(multiset(select level from dual...
In what areas might the use of F# be more appropriate than C#? [closed]
...a structures used to represent program code in F# are mostly discriminated unions (which are not supported in C# in any reasonable way) and this makes a huge difference for this kind of application (where you need to process tree structures, such as program code). Discriminated unions and pattern ma...
How do Python functions handle the types of the parameters that you pass in?
...tively.
Iterable - useful for generators.
Any - when it could be anything.
Union - when it could be anything within a specified set of types, as opposed to Any.
Optional - when it might be None. Shorthand for Union[T, None].
TypeVar - used with generics.
Callable - used primarily for functions, but ...
How to filter SQL results in a has-many-through relation
...RE NOT EXISTS (
SELECT *
FROM (
SELECT 30 AS club_id
UNION ALL
SELECT 50
) AS c
WHERE NOT EXISTS (
SELECT *
FROM student_club AS sc
WHERE sc.stud_id = s.stud_id
AND sc.club_id = c.club_id
)
);
As expected, those two pe...