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A relational database management system uses SQL MERGE (also called upsert) statements to INSERT new records or UPDATE or DELETE existing records depending on whether condition matches. It was officially introduced in the SQL:2003 standard, and expanded [citation needed] in the SQL:2008 standard.
The sort-merge join (also known as merge join) is a join algorithm and is used in the implementation of a relational database management system. The basic problem of a join algorithm is to find, for each distinct value of the join attribute, the set of tuples in each relation which display that value. The key idea of the sort-merge algorithm is ...
Subsets of data can be selected by column name, index, or Boolean expressions. For example, df[df['col1'] > 5] will return all rows in the DataFrame df for which the value of the column col1 exceeds 5. [4]: 126–128 Data can be grouped together by a column value, as in df['col1'].groupby(df['col2']), or by a function which is applied to the index.
Dataframe may refer to: A tabular data structure common to many data processing libraries: pandas (software) § DataFrames; The Dataframe API in Apache Spark;
In the merge sort algorithm, this subroutine is typically used to merge two sub-arrays A[lo..mid], A[mid+1..hi] of a single array A. This can be done by copying the sub-arrays into a temporary array, then applying the merge algorithm above. [1] The allocation of a temporary array can be avoided, but at the expense of speed and programming ease.
Merge algorithm, an algorithm for combining two or more sorted lists into a single sorted one; Mail merge, the production of multiple documents from a single template form and a structured data source; Randomness merger, a function which combines several, perhaps correlated, random variables into one high-entropy random variable
By Brendan Pierson (Reuters) -Idaho can enforce a first-of-its-kind "abortion trafficking" law against those who harbor or transport a minor to get an abortion out of state without parental ...
Three-way merge based revision control tools are widespread, but the technique fundamentally depends on finding a common ancestor of the versions to be merged. There are awkward cases, particularly the "criss-cross merge", [ 3 ] where a unique last common ancestor of the modified versions does not exist.