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MySQL error: key specification without a key length
I have a table with a primary key that is a varchar(255). Some cases have arisen where 255 characters isn't enough. I tried changing the field to a text, but I get the following error:
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Select Last Row in the Table
I would like to retrieve the last file inserted into my table. I know that the method first() exists and provides you with the first file in the table but I don't know how to get the last insert.
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How do MySQL indexes work?
...ically, how can they return the data requested without scanning the entire table?
8 Answers
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SQL SELECT speed int vs varchar
I'm in the process of creating a table and it made me wonder.
9 Answers
9
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How to Use slideDown (or show) function on a table row?
I'm trying to add a row to a table and have that row slide into view, however the slidedown function seems to be adding a display:block style to the table row which messes up the layout.
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difference between primary key and unique key
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Primary Key:
There can only be one primary key in a table
In some DBMS it cannot be NULL - e.g. MySQL adds NOT NULL
Primary Key is a unique key identifier of the record
Unique Key:
Can be more than one unique key in one table
Unique key can have NULL values
It can be a can...
Deleting rows with MySQL LEFT JOIN
I have two tables, one for job deadlines, one for describe a job. Each job can take a status and some statuses means the jobs' deadlines must be deleted from the other table.
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Real life example, when to use OUTER / CROSS APPLY in SQL
...ORDER BY pr.name) pa
ORDER BY pr.name,
pa.name
2) Calling a Table Valued Function for each row in the outer query
SELECT *
FROM sys.dm_exec_query_stats AS qs
CROSS APPLY sys.dm_exec_query_plan(qs.plan_handle)
3) Reusing a column alias
SELECT number,
doubled_number,
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How does a hash table work?
I'm looking for an explanation of how a hash table works - in plain English for a simpleton like me!
15 Answers
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Which data type for latitude and longitude?
... want to store latitude and longitude values in PostgreSQL 9.1.1 database table. I will calculate distance between two points, find nearer points by using this location values.
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