A FULL OUTER join would return a record set that contains all the records from these three different sets 1, 2 and 3. And Set 3 is the set of records in Table B that do not match any records in Table A. Set 2 is the set of records in Table A that do not match any records in Table B. Set 1 is the set of records in Table A and B that meet the join criteria. The three different sets are represented by the three different sections created by the intersection of the two different circles, labeled Set 1, Set 2 and Set 3. In the above diagram, the two tables are represented by the two circles, labeled Table A, and Table B. The following diagram illustrates the three different sets: And the last set of records is the set of records in the right table that do not have matching records in the left table. The second set of records is the set of records in the left table that do not meet the join criteria, or are said to not have matching records in the right table. ![]() This is the set produced when you perform an INNER JOIN. The first record set contains only those records meeting the join criteria. When you join two tables you can think of the records involved falling into three different unique record sets. For each record returned that does not have matching records in the corresponding set, a NULL value will be returned for each column selected from the corresponding set. What is a FULL OUTER Join?Ī FULL OUTER join operation on two record sets returns all of the records contained in both sets even if they do not meet the join criteria. This article will show you how you can write some SQL code in Access to implement a simulated FULL OUTER JOIN. ![]() If you need to perform a FULL OUTER JOIN in Access, are you “up a creek, without a paddle”? No, you are not. The first three of these different join types are implemented in Access, but FULL OUTER JOIN is not. There are many different kinds of joins, like INNER JOIN, LEFT OUTER JOIN, RIGHT OUTER JOIN, and FULL OUTER JOIN.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |