大约有 40,000 项符合查询结果（耗时：0.0243秒） [XML]
Select row with most recent date per user
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Query:
SQLFIDDLEExample
SELECT t1.*
FROM lms_attendance t1
WHERE t1.time = (SELECT MAX(t2.time)
FROM lms_attendance t2
WHERE t2.user = t1.user)
Result:
| ID | USER | TIME | IO |
---------------------------...
How do I get list of all tables in a database using TSQL?
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SQL Server 2000, 2005, 2008, 2012, 2014, 2016, 2017 or 2019:
SELECT * FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_TYPE='BASE TABLE'
To show only tables from a particular database
SELECT TABLE_NAME
FROM <DATABASE_NAME>.INFORMATION_SCHEMA.TABLES
WHERE TABLE_TYPE = 'BASE TABLE'...
Use variable with TOP in select statement in SQL Server without making it dynamic [duplicate]
...es, in SQL Server 2005 it's possible to use a variable in the top clause.
select top (@top) * from tablename
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Oracle SQL: Update a table with data from another table
...his is called a correlated update
UPDATE table1 t1
SET (name, desc) = (SELECT t2.name, t2.desc
FROM table2 t2
WHERE t1.id = t2.id)
WHERE EXISTS (
SELECT 1
FROM table2 t2
WHERE t1.id = t2.id )
Assuming the join results in a key-pr...
How to check if an option is selected?
...
UPDATE
A more direct jQuery method to the option selected would be:
var selected_option = $('#mySelectBox option:selected');
Answering the question .is(':selected') is what you are looking for:
$('#mySelectBox option').each(function() {
if($(this).is(':selected')) ....
Best way to unselect a in jQuery?
What is the best way, using jQuery, to elegantly unselect the option?
15 Answers
15
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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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What's faster, SELECT DISTINCT or GROUP BY in MySQL?
...'t, then use DISTINCT.
GROUP BY in MySQL sorts results. You can even do:
SELECT u.profession FROM users u GROUP BY u.profession DESC
and get your professions sorted in DESC order.
DISTINCT creates a temporary table and uses it for storing duplicates. GROUP BY does the same, but sortes the disti...
Using group by on multiple columns
..., to do with who is attending what subject at a university:
Table: Subject_Selection
+---------+----------+----------+
| Subject | Semester | Attendee |
+---------+----------+----------+
| ITB001 | 1 | John |
| ITB001 | 1 | Bob |
| ITB001 | 1 | Mickey |
| ITB001 ...
Row count with PDO
...
$sql = "SELECT count(*) FROM `table` WHERE foo = ?";
$result = $con->prepare($sql);
$result->execute([$bar]);
$number_of_rows = $result->fetchColumn();
Not the most elegant way to do it, plus it involves an extra query...