大约有 47,000 项符合查询结果（耗时：0.0175秒） [XML]
Select row with most recent date per user
...
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 to request a random row in SQL?
...
See this post: SQL to Select a random row from a database table. It goes through methods for doing this in MySQL, PostgreSQL, Microsoft SQL Server, IBM DB2 and Oracle (the following is copied from that link):
Select a random row with MySQL:
SELE...
Difference between left join and right join in SQL Server [duplicate]
...
Select * from Table1 left join Table2 ...
and
Select * from Table2 right join Table1 ...
are indeed completely interchangeable. Try however Table2 left join Table1 (or its identical pair, Table1 right join Table2) to see...
Table name as variable
...mpare data between the same tables of different databases:
static query:
SELECT * FROM [DB_ONE].[dbo].[ACTY]
EXCEPT
SELECT * FROM [DB_TWO].[dbo].[ACTY]
since I want easily change tha name of table and schema I have created this dynamic query:
declare @schema varchar(50)
declare @table varchar(5...
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...
Get top n records for each group of grouped results
...ould need to specify the group number and add queries for each group:
(
select *
from mytable
where `group` = 1
order by age desc
LIMIT 2
)
UNION ALL
(
select *
from mytable
where `group` = 2
order by age desc
LIMIT 2
)
There are a variety of ways to do this, see this articl...
Return a value if no rows are found in Microsoft tSQL
...
SELECT CASE WHEN COUNT(1) > 0 THEN 1 ELSE 0 END AS [Value]
FROM Sites S
WHERE S.Id = @SiteId and S.Status = 1 AND
(S.WebUserId = @WebUserId OR S.AllowUploads = 1)
...
How to disable text selection highlighting
...S standard way to disable the highlighting effect if the user accidentally selects the text?
48 Answers
...
How to add extra info to copied web text
...cument.location.href}`;
event.clipboardData.setData('text', document.getSelection() + pagelink);
event.preventDefault();
});
Lorem ipsum dolor sit amet, consectetur adipiscing elit.<br/>
<textarea name="textarea" rows="7" cols="50" placeholder="paste your copied text here"></...
How can I generate an INSERT script for an existing SQL Server table that includes all stored rows?
...l need to run it at the database level.
Right-click the database in SSMS, select "Tasks", "Generate Scripts...". As you work through, you'll get to a "Scripting Options" section. Click on "Advanced", and in the list that pops up, where it says "Types of data to script", you've got the option to s...