


How Can I Simulate an Upsert Operation in Microsoft Access Using SQL Queries?
Jan 19, 2025 pm 08:01 PMUse simulated query to perform Upsert operation in Microsoft Access
In Microsoft Access, the Upsert operation (update row if it exists, insert row if it does not exist) can be simulated using UPDATE query combined with LEFT JOIN. This approach allows a single query to handle both cases.
To perform an Upsert operation, follow these steps:
- Create an UPDATE query to set the desired values ??for columns in existing rows:
UPDATE ... SET <column1> = <value1>, <column2> = <value2>, ... WHERE <key_column> = <key_value>
- Use LEFT JOIN to join an UPDATE query with a temporary table or subquery containing the new values:
UPDATE b LEFT JOIN a ON b.id = a.id SET a.f1 = b.f1, a.f2 = b.f2, a.f3 = b.f3
In this example, table b represents the source of the new values ??and table a represents the target table. LEFT JOIN pairs matching rows from two tables based on a common column id.
This combined query will first try to update existing rows in table a whose id column matches table b. If no matching row is found in table a, the new value is inserted as a new row.
Alternatively, you can use the following query form for easier understanding:
UPDATE main_table RIGHT JOIN new_data ON main_table.id = new_data.id SET main_table.id = new_data.id, main_table.col_1 = new_data.col_1, main_table.col_2 = new_data.col_2
This emulates Upsert behavior by first trying to update the row and inserting a new row if the join does not match any existing row in main_table.
The above is the detailed content of How Can I Simulate an Upsert Operation in Microsoft Access Using SQL Queries?. For more information, please follow other related articles on the PHP Chinese website!

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