Show the Collation in MariaDB

In MariaDB, collation can be applied at many levels. Collation can be applied at the server level, the connection level, the database level, the table level, and even at the column level.

It’s also possible to specify a collation at the query level, so that it will override any collation that has been applied at the database, table, or column levels.

MariaDB provides a number of options for returning the collation at the various levels.

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Return the Partition Number for Each Row When Querying a Partitioned Table in SQL Server (T-SQL)

If you’ve got a partitioned table in SQL Server, and you now want to run a query that includes the partition number on each row returned by the query, you can use the $PARTITION system function to do just that.

The $PARTITION function returns the partition number into which a set of partitioning column values would be mapped for any specified partition function.

You can therefore use it in your SELECT statement to return the partition that each row belongs to.

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How to Delete MongoDB Documents by Importing a File

As of mongoimport version 100.0.0, you can delete documents in MongoDB based on an imported file. To do this, use delete mode.

When you use delete mode, if an imported document has the same _id value as an existing one in the collection that you’re importing into, the existing document will be deleted.

You can also specify another field or fields (other than the _id field) to be the matching field if required.

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