March 20th, 2010
Union
Posted by
admin in
B. SQL Basics
A table “union” means that the rows of one table are combined under the rows of another table. Unions are rarely used.
Table A:
Table B:
Result table of a union:
The definition (data type) and number of columns in the first table must exactly match the definition and number of columns in the second table. Since the source tables may have different column names, the result table has no column names.
