大约有 43,000 项符合查询结果（耗时：0.0364秒） [XML]
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 ...
What is the difference between std::array and std::vector? When do you use one over other? [duplicat
...inter to an array; e.g., C library routines. (As an aside, std::vector<char> buf(8192); is a great way to allocate a local buffer for calls to read/write or similar without directly invoking new.)
That said, the lack of that extra level of indirection, plus the compile-time constant size, ca...
How to delete duplicates on a MySQL table?
...n an index is going to be slow for large tables. Wouldn't it be better to SELECT MAX(ID) FROM t GROUP BY unique and then JOIN to an exact match of ID to MAX(ID)?
– ebyrob
Nov 10 '16 at 16:31
...
Oracle SQL Query for listing all Schemas in a DB
...
Using sqlplus
sqlplus / as sysdba
run:
SELECT *
FROM dba_users
Should you only want the usernames do the following:
SELECT username
FROM dba_users
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Select N random elements from a List in C#
I need a quick algorithm to select 5 random elements from a generic list. For example, I'd like to get 5 random elements from a List<string> .
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Get top 1 row of each group
...
;WITH cte AS
(
SELECT *,
ROW_NUMBER() OVER (PARTITION BY DocumentID ORDER BY DateCreated DESC) AS rn
FROM DocumentStatusLogs
)
SELECT *
FROM cte
WHERE rn = 1
If you expect 2 entries per day, then this will arbitrarily pick one...
How to prevent line break at hyphens on all browsers
...liably than splitting the text to “words” (sequences of non-whitespace characters separated by whitespace) and wrapping each “word” that contains a hyphen inside nobr markup. So input data like bla bla foo-bar bla bla would be turned to bla bla <nobr>foo-bar</nobr> bla bla.
You ...
how do I query sql for a latest record date for each user
...
select t.username, t.date, t.value
from MyTable t
inner join (
select username, max(date) as MaxDate
from MyTable
group by username
) tm on t.username = tm.username and t.date = tm.MaxDate
...
Return rows in random order [duplicate]
...
SELECT * FROM table
ORDER BY NEWID()
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How do I add options to a DropDownList using jQuery?
...lugins,
var myOptions = {
val1 : 'text1',
val2 : 'text2'
};
var mySelect = $('#mySelect');
$.each(myOptions, function(val, text) {
mySelect.append(
$('<option></option>').val(val).html(text)
);
});
If you had lots of options, or this code needed to be run very ...