大约有 40,000 项符合查询结果（耗时：0.0258秒） [XML]
Fetch the row which has the Max value for a column
... multiple rows for the userid where the maximum date is on multiple rows.
select userid,
my_date,
...
from
(
select userid,
my_date,
...
max(my_date) over (partition by userid) max_my_date
from users
)
where my_date = max_my_date
"Analytic functions rock"
Edi...
Oracle: If Table Exists
...
declare
c int;
begin
select count(*) into c from user_tables where table_name = upper('table_name');
if c = 1 then
execute immediate 'drop table table_name';
end if;
end;
That's for checking whether a table in the current schema exi...
Hibernate dialect for Oracle Database 11g?
...e getQuerySequencesString() method, that returns this query:
"select sequence_name from user_sequences;"
for which the execution returns an empty result from database).
Using the dialect org.hibernate.dialect.Oracle9iDialect , or greater, solves the problem, due to a di...
Count with IF condition in MySQL query
...
Use sum() in place of count()
Try below:
SELECT
ccc_news . * ,
SUM(if(ccc_news_comments.id = 'approved', 1, 0)) AS comments
FROM
ccc_news
LEFT JOIN
ccc_news_comments
ON
ccc_news_comments.news_id = ccc_news.news_id
WHERE
`ccc_...
Making heatmap from pandas DataFrame
...sinstance(index, pd.DatetimeIndex):
idx = pd.DatetimeIndex(middle).union([start,end])
elif isinstance(index, (pd.Float64Index,pd.RangeIndex,pd.Int64Index)):
idx = pd.Float64Index(middle).union([start,end])
else:
print('Warning: guessing what to do with index type %s' ...
What is __init__.py for?
...ll fail.
The __init__.py file is usually empty, but can be used to export selected portions of the package under more convenient name, hold convenience functions, etc.
Given the example above, the contents of the init module can be accessed as
import spam
based on this
...
How can I use UUIDs in SQLAlchemy?
...cause it implicitly tries to do some sort of character conversion for the "select * from table where id =..." and there's miscellaneous display issues.
Other than that everything seems to work fine, and so I'm throwing it out there. Leave a comment if you see a glaring error with it. I welcome any ...
WAMP/XAMPP is responding very slow over localhost
...\Services\TCPIP6\Parameters
Right click on Parameters, expand New, and select DWORD (32-bit) Value
Enter DisabledComponents into the Name field
Double click on the new DisabledComponents value, enter ffffffff into the Value data dialog box, and click the OK button
Confirm the new regist...
Selecting only first-level elements in jquery
How can I select the link elements of only the parent <ul> from a list like this?
10 Answers
...
Merging two arrays in .NET
...ew[] { 1, 2, 3, 4, 5 };
var arr2 = new[] { 6, 7, 8, 9, 0 };
var arr = arr1.Union(arr2).ToArray();
Keep in mind, this will remove duplicates. If you want to keep duplicates, use Concat.
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