大约有 43,000 项符合查询结果（耗时：0.0492秒） [XML]
How to concatenate text from multiple rows into a single text string in SQL server?
...y, John, Sam
2 Alaina, Edward
I used the following T-SQL:
SELECT Main.SubjectID,
LEFT(Main.Students,Len(Main.Students)-1) As "Students"
FROM
(
SELECT DISTINCT ST2.SubjectID,
(
SELECT ST1.StudentName + ',' AS [text()]
FR...
How do I perform an IF…THEN in an SQL SELECT?
How do I perform an IF...THEN in an SQL SELECT statement?
30 Answers
30
...
What's the difference between KeyDown and KeyPress in .NET?
...ctical difference between KeyDown and KeyPress is that KeyPress relays the character resulting from a keypress, and is only called if there is one.
In other words, if you press A on your keyboard, you'll get this sequence of events:
KeyDown: KeyCode=Keys.A, KeyData=Keys.A, Modifiers=Keys.None
Key...
Create a temporary table in a SELECT statement without a separate CREATE TABLE
Is it possible to create a temporary (session only) table from a select statement without using a create table statement and specifying each column type? I know derived tables are capable of this, but those are super-temporary (statement-only) and I want to re-use.
...
Using LIMIT within GROUP BY to get N results per group?
...to get all years into a single column, grouped by id and ordered by rate:
SELECT id, GROUP_CONCAT(year ORDER BY rate DESC) grouped_year
FROM yourtable
GROUP BY id
Result:
-----------------------------------------------------------
| ID | GROUPED_YEAR |...
Simplest way to do a recursive self-join?
...
WITH q AS
(
SELECT *
FROM mytable
WHERE ParentID IS NULL -- this condition defines the ultimate ancestors in your chain, change it as appropriate
UNION ALL
SELECT m.*
FROM mytable m
...
Is there any difference between GROUP BY and DISTINCT
...CT and distinct by UNION cause an oracle error, but GROUP BY worked; I was selecting only 1 column from a view and not using any aggregation; I'm still baffled why it required it, but it does confirm there is some difference in the execution. As others point out, it also lets you GROUP BY columns no...
Add centered text to the middle of a -like line
... be specified in em units. To get hr width, use (.divider width minus # of chars) / 2 .
– Kelvin
Jan 31 '13 at 22:38
13
...
How to retrieve the current value of an oracle sequence without increment it?
...
SELECT last_number
FROM all_sequences
WHERE sequence_owner = '<sequence owner>'
AND sequence_name = '<sequence_name>';
You can get a variety of sequence metadata from user_sequences, all_sequences and dba_...
How to “git show” a merge commit with combined diff output even when every changed file agrees with
...ng this on the git repository on a8e4a59 shows a combined diff (plus/minus chars in one of 2 columns). As the git-show manual mentions, it pretty much delegates to 'git diff-tree' so those options look useful.
share
...