Tutorial by Topics: merge

MERGE (often also called UPSERT for "update or insert") allows to insert new rows or, if a row already exists, to update the existing row. The point is to perform the whole set of operations atomically (to guarantee that the data remain consistent), and to prevent communication overhead fo...

DataFrame.merge(right, how='inner', on=None, left_on=None, right_on=None, left_index=False, right_index=False, sort=False, suffixes=('_x', '_y'), copy=True, indicator=False) Merge DataFrame objects by performing a database-style join operation by columns or indexes. If joining columns ...

Starting with SQL Server 2008, it is possible to perform insert, update, or delete operations in a single statement using the MERGE statement. The MERGE statement allows you to join a data source with a target table or view, and then perform multiple actions against the target based on the results ...

A join combines two tables containing related columns. The term covers a wide range of operations, essentially everything except appending the two tables. "Merge" is a synonym. Type ?`[.data.table` for the official docs. x[i, on, j] # join: data.table x & data.table or list i x[!i...

Sqoop incremental import comes into picture because of a phenomenon called CDC i.e. Change Data Capture. Now what is CDC? CDC is a design pattern that captures individual data changes instead of dealing with the entire data. Instead of dumping our entire database, using CDC, we could capture ju...

The MERGE statement will merge one or more like formatted COBOL data files into a single output file. The programmer can assume control over theOUTPUT PROCEDURE, which uses the RELEASE statement, or use internal COBOL runtime mechanisms with the GIVING clause.

How to merge cells