Assume the following query runs correctly:

SELECT CustomerName, City
FROM Customers;

I could re-write the query as follows and it would also run correctly. True or false?

SELECT Customers.CustomerName, Customers.City
FROM Customers;

Question

Assume the following query runs correctly:

SELECT CustomerName, City
FROM Customers;

I could re-write the query as follows and it would also run correctly. True or false?

SELECT Customers.CustomerName, Customers.City
FROM Customers;

BlackTom AI · Accepted Answer

The question asks whether re-writing a simple SELECT query to use fully qualified column names with the table name prefix would still execute correctly.
First, consider the original statement: SELECT CustomerName, City FROM Customers; This selects two columns from the Customers table without prefixing them with the table name. In SQL, if there is only one table in the FROM clause, you can reference columns by their unqualified names.
Second, look at the proposed rewrite: SELECT Customers.CustomerName, Customers.City FROM Customers; Here, each column is explicitly qualified with the table name prefix before the column name. This is standard SQL syntax and is valid as long as the table name is correct and the columns exist on that table. Since the FROM clause still references the same table (Customers) and the column names (CustomerName and City) exist on that table, this query will run without error.
Third, consider potential edge cases. The use of table prefixes helps disambiguate in queries involving multiple tables or joins. In this simple query with a single table, there is no ambiguity, so both forms are equally valid. If there were multiple tables with overlapping column names, qualifying columns would be necessary; but that does not affect this scenario.
In summary, the rewritten query with the fully-qualified column references is syntactically correct and semantically equivalent to the original, so the statement is true.

HADM3740/HADM6740 Querying 1 Quiz

Assume the following query runs correctly: SELECT CustomerName, City FROM Customers; I could re-write the query as follows and it would also run correctly. True or false? SELECT Customers.CustomerName, Customers.City FROM Customers;

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