How to Efficiently Query Multiple Columns with the SQL IN Clause?

SQL IN Clause for Multiple Columns

When performing a query on a table based on multiple columns using the IN clause, constructing a single query with multiple OR conditions becomes tedious. Instead, one can utilize the following approaches:

Using Tuple IN Clause

The most direct solution is to use the tuple version of the IN clause. For instance, given the User table with firstName, lastName, and City columns, the query to retrieve cities for a list of (firstName, lastName) tuples would be:

SELECT City
FROM User
WHERE (firstName, lastName) IN (('a', 'b'), ('c', 'd'));

Creating a Staging Table

Another option is to create a staging table with all possible (firstName, lastName) combinations and then perform a join between this table and the User table. However, this method requires additional setup and maintenance, which may not be ideal for large datasets.

Recommendations

For general scenarios, the tuple IN clause approach is preferred due to its simplicity and flexibility. It eliminates the need for complex query construction or additional tables. However, if the search data is stored outside the database, then alternative methods such as joins or subqueries may be necessary.

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