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CSS vertical alignment text inside li
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Define the parent with display: table and the element itself with vertical-align: middle and display: table-cell.
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How do SQL EXISTS statements work?
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For 'each' row from Suppliers, check if there 'exists' a row in the Order table that meets the condition Suppliers.supplier_id (this comes from Outer query current 'row') = Orders.supplier_id. When you find the first matching row, stop right there - the WHERE EXISTS has been satisfied.
The magic ...
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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SQL SELECT speed int vs varchar
I'm in the process of creating a table and it made me wonder.
9 Answers
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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...
How do MySQL indexes work?
...ically, how can they return the data requested without scanning the entire table?
8 Answers
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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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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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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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