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Can you use an alias in the WHERE clause in mysql?
...will not work, in which case you'll need to use a HAVING clause.
From the MySQL Manual:
It is not allowable to refer to a
column alias in a WHERE clause,
because the column value might not yet
be determined when the WHERE clause
is executed. See Section B.1.5.4,
“Problems with Colu...
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Best way to make Django's login_required the default
... Simply check each view function.
import os
import re
def view_modules( root ):
for path, dirs, files in os.walk( root ):
for d in dirs[:]:
if d.startswith("."):
dirs.remove(d)
for f in files:
name, ext = os.path.splitext(f)
...
Adding multiple columns AFTER a specific column in MySQL
...ermitted in a single ALTER TABLE statement, separated by commas. This is a MySQL extension to standard SQL, which permits only one of each clause per ALTER TABLE statement.
– informatik01
May 1 '19 at 13:21
...
When to use MyISAM and InnoDB? [duplicate]
...
Read about Storage Engines.
MyISAM:
The MyISAM storage engine in MySQL.
Simpler to design and create, thus better for beginners. No worries about the foreign relationships between tables.
Faster than InnoDB on the whole as a result of the simpler structure thus much less costs of server ...
Alter MySQL table to add comments on columns
I have been checking the MySQL Documentation for ALTER TABLE and it does not seem to include a way to add or modify a comment to a column. How can I do this?
...
How to update column with null value
I am using mysql and need to update a column with a null value. I have tried this many different ways and the best I have gotten is an empty string.
...
ROW_NUMBER() in MySQL
Is there a nice way in MySQL to replicate the SQL Server function ROW_NUMBER() ?
24 Answers
...
Set NOW() as Default Value for datetime datatype?
...
As of MySQL 5.6.5, you can use the DATETIME type with a dynamic default value:
CREATE TABLE foo (
creation_time DATETIME DEFAULT CURRENT_TIMESTAMP,
modification_time DATETIME ON UPDATE CURRENT_TIMESTAMP
)
Or even...
MySQL - Make an existing Field Unique
...
ALTER IGNORE TABLE mytbl ADD UNIQUE (columnName);
For MySQL 5.7.4 or later:
ALTER TABLE mytbl ADD UNIQUE (columnName);
As of MySQL 5.7.4, the IGNORE clause for ALTER TABLE is removed and
its use produces an error.
So, make sure to remove duplicate entries first as IGNO...