Description: The SQL operation ‘Union All’ (UNION ALL) is a fundamental tool in Structured Query Language (SQL) that allows combining the results of multiple SELECT statements into a single result table. Unlike the UNION operation, which removes duplicates, UNION ALL includes all records, even those that are identical. This feature makes it a valuable option when the goal is to retain the entirety of the data, regardless of repetitions. The basic syntax of UNION ALL involves using multiple SELECT queries, each of which can extract data from one or more tables. The results are stacked vertically, meaning that the final result set will have as many rows as the sum of the rows from each individual query. It is important that the queries being combined with UNION ALL have the same number of columns and compatible data types in each position. This operation is particularly useful in scenarios where comprehensive data analysis is required, such as in reports that consolidate information from different sources or in creating views that integrate data from various tables. In summary, UNION ALL is a powerful operation that allows developers and data analysts to effectively manage and present information.
