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mysql_config not found when installing mysqldb python interface
...one Building dependency tree Reading state information...Done Note, selecting libmysqlclient15-dev instead of libmysqlclient-dev Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required...
Select where count of one field is greater than one
...clause, for aggregate result comparison.
Taking the query at face value:
SELECT *
FROM db.table
HAVING COUNT(someField) > 1
Ideally, there should be a GROUP BY defined for proper valuation in the HAVING clause, but MySQL does allow hidden columns from the GROUP BY...
Is this in preparati...
How do I list all the columns in a table?
...
For Oracle (PL/SQL)
SELECT column_name
FROM user_tab_cols
WHERE table_name = 'myTableName'
For MySQL
SHOW COLUMNS FROM table_name
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How to delete a certain row from mysql table with same column values?
...ike this:
DELETE FROM your_table WHERE id_users=1 AND id_product=2
LIMIT (SELECT COUNT(*)-1 FROM your_table WHERE id_users=1 AND id_product=2)
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How to get the max of two values in MySQL?
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Use GREATEST()
E.g.:
SELECT GREATEST(2,1);
Note: Whenever if any single value contains null at that time this function always returns null (Thanks to user @sanghavi7)
s...
MySQL InnoDB not releasing disk space after deleting data rows from table
... recreate your table and regain diskspace
Create TBL_B like TBL_A . Insert select data you want to keep from TBL_A into TBL_B. Drop TBL_A, and rename TBL_B to TBL_A. This way is very effective if TBL_A and data that needed to delete is big (delete command in MySQL innodb is very bad performance)
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How to find elements by class
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CSS selectors
single class first match
soup.select_one('.stylelistrow')
list of matches
soup.select('.stylelistrow')
compound class (i.e. AND another class)
soup.select_one('.stylelistrow.otherclassname')
soup.select('.st...
How do I merge two dictionaries in a single expression in Python (taking union of dictionaries)?
...le expression that returns these two dictionaries, merged (i.e. taking the union). The update() method would be what I need, if it returned its result instead of modifying a dictionary in-place.
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Is gcc's __attribute__((packed)) / #pragma pack unsafe?
...option, enabled by default.
When address of packed member of struct or union is taken, it may
result in an unaligned pointer value. This patch adds
-Waddress-of-packed-member to check alignment at pointer assignment and warn unaligned address as well as unaligned pointer
I've just built t...
Add 2 hours to current time in MySQL?
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SELECT *
FROM courses
WHERE DATE_ADD(NOW(), INTERVAL 2 HOUR) > start_time
See Date and Time Functions for other date/time manipulation.
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