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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.
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ROW_NUMBER() in MySQL
Is there a nice way in MySQL to replicate the SQL Server function ROW_NUMBER() ?
24 Answers
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Set NOW() as Default Value for datetime datatype?
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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
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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...
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MySQL selecting yesterday's date
... would otherwise require a cumbersome and wordy case statement, is that in mysql boolean values are 1 for true and 0 for false, so summing a condition effectively counts how many times it's true. Using this pattern can neaten up your SQL code.
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Sibling package imports
...ern on a regular basis with
# Ugly hack to allow absolute import from the root folder
# whatever its name is. Please forgive the heresy.
if __name__ == "__main__" and __package__ is None:
from sys import path
from os.path import dirname as dir
path.append(dir(path[0]))
__package__ ...
MySQL: Quick breakdown of the types of joins [duplicate]
I would like a quick breakdown of the types of MySQL joins. I know of these, the rest I am not sure what they mean.
3 Answe...
MySQL case sensitive query [duplicate]
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MySQL queries are not case-sensitive by default. Following is a simple query that is looking for 'value'. However it will return 'VALUE', 'value', 'VaLuE', etc…
SELECT * FROM `table` WHERE `column` = 'value'
The good new...
Cast from VARCHAR to INT - MySQL
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Unsigned is working. From when did MySQL changed Integer datatype to Unsigned?
– Lenin Raj Rajasekaran
Aug 26 '12 at 1:36
20
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