大约有 40,000 项符合查询结果（耗时：0.0290秒） [XML]
Combined area of overlapping circles
...d four circles (midpoints and radius) and had to calculate the area of the union of these circles.
14 Answers
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How to convert SQL Query result to PANDAS Data Structure?
...sql
cnxn = pyodbc.connect(connection_info)
cursor = cnxn.cursor()
sql = "SELECT * FROM TABLE"
df = psql.frame_query(sql, cnxn)
cnxn.close()
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XAMPP - MySQL shutdown unexpectedly
...Windows has built-in folder versioning — right click on /mysql/data/ and select Restore previous versions. You can then delete the current contents of the folder and replace it with the older version's contents.
Addendum: To ensure that you don't forget to run XAMPP as an administrator you can ri...
Return rows in random order [duplicate]
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SELECT * FROM table
ORDER BY NEWID()
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What is the difference between single and double quotes in SQL?
...ould be more readable as product_id, so you use either of the following:
SELECT PRODUCT.id AS product_id
SELECT PRODUCT.id 'product_id'
Either works in Oracle, SQL Server, MySQL… but I know some have said that the TOAD IDE seems to give some grief when using the single quotes approach.
You do...
MySQL stored procedure vs function, which would I use when?
...d procedures with ordinary SQL, whilst with stored function you can.
e.g. SELECT get_foo(myColumn) FROM mytable is not valid if get_foo() is a procedure, but you can do that if get_foo() is a function. The price is that functions have more limitations than a procedure.
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When to use Hadoop, HBase, Hive and Pig?
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Consider that you work with RDBMS and have to select what to use - full table scans, or index access - but only one of them.
If you select full table scan - use hive. If index access - HBase.
s...
Oracle PL/SQL - How to create a simple array variable?
... INDEX BY PLS_INTEGER;
employee_array employee_arraytype;
BEGIN
SELECT *
BULK COLLECT INTO employee_array
FROM employee
WHERE department = 10;
--
FOR i IN employee_array.FIRST .. employee_array.LAST
LOOP
-- Do something
END LOOP;
END;
The associative arra...
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 |...
MySQL Workbench Dark Theme
...there somewhere else within the Workbench GUI that I need to go to see and select a theme? Besides under "Edit->Preferences-> Fonts & Colors
– edo101
May 7 at 18:54
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