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SQL Server indexes - ascending or descending, what difference does it make?
...rily matters when used with composite indexes:
CREATE INDEX ix_index ON mytable (col1, col2 DESC);
can be used for either:
SELECT *
FROM mytable
ORDER BY
col1, col2 DESC
or:
SELECT *
FROM mytable
ORDER BY
col1 DESC, col2
, but not for:
SELECT *
FROM mytable
ORDE...
Change a column type from Date to DateTime during ROR migration
...
First in your terminal:
rails g migration change_date_format_in_my_table
Then in your migration file:
For Rails >= 3.2:
class ChangeDateFormatInMyTable < ActiveRecord::Migration
def up
change_column :my_table, :my_column, :datetime
end
def down
change_column :my_tabl...
How should I store GUID in MySQL tables?
...the intention of representing said value with a value mapped from a lookup table (in most cases now, UTF8). A BINARY field expects the same kind of value without any intention of representing said data from a lookup table. I used CHAR(16) back in the 4.x days because back then MySQL wasn't as good a...
Keeping it simple and how to do multiple CTE in a query
I have this simple T-SQL query, it emits a bunch of columns from a table and also joins information from other related tables.
...
Create boolean column in MySQL with false as default value?
I want to create a table in MySQL with a boolean column whose default value is false . But it's accepting NULL as default...
...
What do column flags mean in MySQL Workbench?
In MySQL Workbench table editor there are 7 column flags available: PK, NN, UQ, BIN, UN, ZF, AI.
3 Answers
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Can I change a column from NOT NULL to NULL without dropping it?
Need to alter a table to allow nulls on a column -- but cant drop the column...can I do this? Was trying something like:
3...
MySQL case sensitive query [duplicate]
.... However it will return 'VALUE', 'value', 'VaLuE', etc…
SELECT * FROM `table` WHERE `column` = 'value'
The good news is that if you need to make a case-sensitive query, it is very easy to do using the BINARY operator, which forces a byte by byte comparison:
SELECT * FROM `table` WHERE BINARY ...
SQL Server : GROUP BY clause to get comma-separated values [duplicate]
...ECT ReportId, Email =
STUFF((SELECT ', ' + Email
FROM your_table b
WHERE b.ReportId = a.ReportId
FOR XML PATH('')), 1, 2, '')
FROM your_table a
GROUP BY ReportId
SQL fiddle demo
sha...
SQL: How to perform string does not equal
...
Try the following query
select * from table
where NOT (tester = 'username')
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