Metadata
- Author: Keith Dvorjak
- Full Title: Sql
- Category:
Highlights
UNION clause is required to combine the results of two or more select statements in a single table. However, it is important that the results of both the queries have same number of columns with compatible data types or else it will not be possible to achieve union results. (Location 62)
The difference between UNION and UNION ALL is that when you use UNION ALL in your query the result set would display duplicate rows, which is not the case with usage of UNION. (Location 151)