大约有 44,000 项符合查询结果（耗时：0.0306秒） [XML]
Which is fastest? SELECT SQL_CALC_FOUND_ROWS FROM `table`, or SELECT COUNT(*)
...irm this - I just updated a query with 4 joins on a 168,000 row database. Selecting just the first 100 rows with a SQL_CALC_FOUND_ROWS took over 20 seconds; using a separate COUNT(*) query took under 5 seconds (for both count + results queries).
– Sam Dufel
Ju...
How to change options of with jQuery?
Suppose a list of options is available, how do you update the <select> with new <option> s?
9 Answers
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How to select between brackets (or quotes or …) in Vim?
...Computed solution coefficients:
As CMS noted, this works for visual mode selection as well - just use vi), vi}, vi', etc.
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Is there a way to access the “previous row” value in a SELECT statement?
...d to order by some column for this to be meaningful. Something like this:
select t1.value - t2.value from table t1, table t2
where t1.primaryKey = t2.primaryKey - 1
If you know how to order things but not how to get the previous value given the current one (EG, you want to order alphabetically) ...
How to select rows that have current day's timestamp?
I am trying to select only today's records from a database table.
9 Answers
9
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What is the difference between the states selected, checked and activated in Android?
...below added):
... For example, in a list view with single or multiple selection
enabled, the views in the current selection set are activated. (Um,
yeah, we are deeply sorry about the terminology here.) The activated
state is propagated down to children of the view it is set on.
So here...
Search All Fields In All Tables For A Specific Value (Oracle)
...based on
what I think it should be named but it
returned no results.*
SELECT * from dba_objects WHERE
object_name like '%DTN%'
A column isn't an object. If you mean that you expect the column name to be like '%DTN%', the query you want is:
SELECT owner, table_name, column_name FROM all_tab...
Reference alias (calculated in SELECT) in WHERE clause
The calculated value BalanceDue that is set as a variable in the list of selected columns cannot be used in the WHERE clause.
...
postgresql: INSERT INTO … (SELECT * …)
...ostgres
CREATE TABLE tblA (id serial, time integer);
INSERT INTO tblA
SELECT id, time
FROM dblink('dbname=dbtest', 'SELECT id, time FROM tblB')
AS t(id integer, time integer)
WHERE time > 1000;
TABLE tblA;
id | time
----+------
1 | 5000
2 | 2000
(2 rows)
PostgreSQL has ...
Programmatically selecting text in an input field on iOS devices (mobile Safari)
How do you programmatically select the text of an input field on iOS devices, e.g. iPhone, iPad running mobile Safari?
10 A...