大约有 40,000 项符合查询结果（耗时：0.0426秒） [XML]
PostgreSQL LIKE query performance variations
... gist_trgm_ops);
Difference between GiST and GIN index
Example query:
SELECT * FROM tbl WHERE col LIKE '%foo%'; -- leading wildcard
SELECT * FROM tbl WHERE col ILIKE '%foo%'; -- works case insensitively as well
Trigrams? What about shorter strings?
Words with less than 3 letters in indexed...
Random record in ActiveRecord
...he first, all after are still sorted by id). If you need multiple randomly selected records you must use this approach multiple times or use the random order method provided by your database, i.e. Thing.order("RANDOM()").limit(100) for 100 randomly selected entries. (Be aware that it's RANDOM() in P...
Comment shortcut Android Studio
... @PeterSmith Yes, but it still disrupts it. Try it for yourself; select some block of code with documentation, and press Ctrl + Shift + / twice
– Jacob R
Nov 26 '15 at 16:01
...
Oracle取前N条记录方法 Oracle实现SELECT TOP N的方法 - 数据库(内核) - 清...
Oracle取前N条记录方法 Oracle实现SELECT TOP N的方法select * from ( select * from tablexxx order by xxx desc ) where rownum <= Noracle数据库不支持mysql中limit, top功...select * from ( select * from tablexxx order by xxx desc ) where rownum <= N
oracle数据库不支持mysql中li...
Proper way to rename solution (and directories) in Visual Studio
...story of the file. For example, with TortoiseSVN, right click on the file, select TortoiseSVN .. Rename.
In the .sln file, edit all instances of Project1 to be Project2, using a text editor like NotePad.
Restart Visual Studio, and everything will work as before, but with the project in a different ...
How do I find a default constraint using INFORMATION_SCHEMA?
...our constraints!)
-- returns name of a column's default value constraint
SELECT
default_constraints.name
FROM
sys.all_columns
INNER JOIN
sys.tables
ON all_columns.object_id = tables.object_id
INNER JOIN
sys.schemas
ON tables.schema_id = schemas.s...
What's the fastest way to do a bulk insert into Postgres?
...200, 300]),
UNNEST(ARRAY['a', 'b', 'c'])
);
without VALUES using subselect with additional existance check:
INSERT INTO tablename (fieldname1, fieldname2, fieldname3)
SELECT * FROM (
SELECT UNNEST(ARRAY[1, 2, 3]),
UNNEST(ARRAY[100, 200, 300]),
UNNEST(ARRAY['a', 'b...
Visual Studio opens the default browser instead of Internet Explorer
...er:
1) Right click on a .aspx page in your
solution explorer
2) Select the "browse with" context
menu option
3) In the dialog you can select or add
a browser. If you want Firefox in the
list, click "add" and point to the
firefox.exe filename
4) Click the "Set as Default...
What are the differences between a clustered and a non-clustered index?
...than a clustered index
Both types of index will improve performance when select data with fields that use the index but will slow down update and insert operations.
Because of the slower insert and update clustered indexes should be set on a field that is normally incremental ie Id or Timestamp.
...
SQL Joins Vs SQL Subqueries (Performance)?
...e result i was looking for was 739 elements.
My query at first was this:
SELECT p.id,
p.fixedId,
p.azienda_id,
p.categoria_id,
p.linea,
p.tipo,
p.nome
FROM prodotto p
WHERE p.azienda_id = 2699 AND p.anno = (
SELECT MAX(p2.anno)
FROM prodotto p2
WHERE p2.fixed...