大约有 47,000 项符合查询结果（耗时：0.0272秒） [XML]
GROUP BY with MAX(DATE) [duplicate]
... to your group by clause, otherwise you need to rethink your query.
Try:
SELECT t.Train, t.Dest, r.MaxTime
FROM (
SELECT Train, MAX(Time) as MaxTime
FROM TrainTable
GROUP BY Train
) r
INNER JOIN TrainTable t
ON t.Train = r.Train AND t.Time = r.MaxTime
...
App Inventor 2 SQLite 拓展：超流行兼容主流SQL语法的迷你本地数据库引擎...
...原始调用中指定的标签以及新行或更新行的行 ID。
AfterSelect(tag,rowCount,rows)
此事件在异步 Select 调用后触发。
提供原始调用中指定的标签、返回的行数以及结果行数据。
AfterUpdate(tag,rowCount)
此事件在异步 Update 调用后触发。...
What makes a SQL statement sargable?
...non-sargable is to include a field inside a function in the where clause:
SELECT ... FROM ...
WHERE Year(myDate) = 2008
The SQL optimizer can't use an index on myDate, even if one exists. It will literally have to evaluate this function for every row of the table. Much better to use:
WHERE myDat...
Find the number of columns in a table
...
SELECT COUNT(*)
FROM INFORMATION_SCHEMA.COLUMNS
WHERE table_catalog = 'database_name' -- the database
AND table_name = 'table_name'
share
...
Are PDO prepared statements sufficient to prevent SQL injection?
....
$pdo->query('SET NAMES gbk');
$var = "\xbf\x27 OR 1=1 /*";
$query = 'SELECT * FROM test WHERE name = ? LIMIT 1';
$stmt = $pdo->prepare($query);
$stmt->execute(array($var));
In certain circumstances, that will return more than 1 row. Let's dissect what's going on here:
Selecting a Cha...
How to set selected item of Spinner by value, not by position?
I have a update view, where I need to preselect the value stored in database for a Spinner.
25 Answers
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How to print SQL statement in codeigniter model
...veRecord generated SQL:
Before the query runs:
$this->db->_compile_select();
And after it has run:
$this->db->last_query();
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List of tables, db schema, dump etc using the Python sqlite3 API
....tab
job snmptarget t1 t2 t3
sqlite> select name from sqlite_master where type = 'table';
job
t1
t2
snmptarget
t3
sqlite> .schema job
CREATE TABLE job (
id INTEGER PRIMARY KEY,
data VARCHAR
);
sqlite> select sql from sqlite_master where type = 'ta...
How to increase storage for Android Emulator? (INSTALL_FAILED_INSUFFICIENT_STORAGE)
...onfigurations". You can find that in the drop-down under the "debug" icon. Select "target", and select a preferred emulator target to launch. Then under "additional emulator command line options," add this:
-partition-size 1024
Then CLOSE the emulator (and remove any devices), and click the debug ...
How do I run Visual Studio as an administrator by default?
...indows 8, 8.1 and 10
In Windows 8, you have to right-click devenv.exe and select "Troubleshoot compatibility".
Select "Troubleshoot program"
Check "The program requires additional permissions"
click "Next", click "Test the program..."
Wait for the program to launch
Click "Next"
Select "Yes, save ...