大约有 43,000 项符合查询结果（耗时：0.0405秒） [XML]
Only one expression can be specified in the select list when the subquery is not introduced with EXI
...column on the other side of the IN. So the query needs to be of the form:
SELECT * From ThisTable WHERE ThisColumn IN (SELECT ThatColumn FROM ThatTable)
You also want to add sorting so you can select just from the top rows, but you don't need to return the COUNT as a column in order to do your so...
How do I pass command line arguments to a Node.js program?
...ecause options that start with a single dash are only supposed to a single character. Anything that follows a single char option is taken as an argument for the option (no space required). Starting the option with two dashes (i.e. --n5) should produce 'n5: true'. This is fairly standard behaviour fo...
How to change Android Studio's editor font?
...TRL + mouse wheel which is really easy to use it !!!
To use this feature select File -> Settings -> Editor -> General -> select the checkbox of Change the font size (Zoom) with Ctrl + Mouse Wheel
I hope it's helpful.
...
select count(*) from table of mysql in php
...s keyword in order to call it from mysql_fetch_assoc
$result=mysql_query("SELECT count(*) as total from Students");
$data=mysql_fetch_assoc($result);
echo $data['total'];
share
|
improve this answ...
Difference between “read commited” and “repeatable read”
...nd consider you have a simple task like the following:
BEGIN TRANSACTION;
SELECT * FROM T;
WAITFOR DELAY '00:01:00'
SELECT * FROM T;
COMMIT;
That is a simple task that issue two reads from table T, with a delay of 1 minute between them.
under READ COMMITTED, the second SELECT may return any da...
Select distinct using linq [duplicate]
...
myList.GroupBy(test => test.id)
.Select(grp => grp.First());
Edit: as getting this IEnumerable<> into a List<> seems to be a mystery to many people, you can simply write:
var result = myList.GroupBy(test => test.id)
.S...
How do you copy a record in a SQL table but swap out the unique id of the new row?
...
Try this:
insert into MyTable(field1, field2, id_backup)
select field1, field2, uniqueId from MyTable where uniqueId = @Id;
Any fields not specified should receive their default value (which is usually NULL when not defined).
...
How can I convert tabs to spaces in every file of a directory?
...s on each line;
-t 4 means that each tab will be converted to 4 whitespace chars (8 by default).
sponge is from the moreutils package, and avoids clearing the input file.
Finally, you can use gexpand on OSX, after installing coreutils with Homebrew (brew install coreutils).
...
SQL: How to properly check if a record exists
...
It's better to use either of the following:
-- Method 1.
SELECT 1
FROM table_name
WHERE unique_key = value;
-- Method 2.
SELECT COUNT(1)
FROM table_name
WHERE unique_key = value;
The first alternative should give you no result or one result, the second count should be zero or on...
Copy data into another table
...
If both tables are truly the same schema:
INSERT INTO newTable
SELECT * FROM oldTable
Otherwise, you'll have to specify the column names (the column list for newTable is optional if you are specifying a value for all columns and selecting columns in the same order as newTable's schema)...