Why Does My PostgreSQL Query Fail with 'Column \'Continent\' Does Not Exist' Despite the Column Existing?

PostgreSQL database error: Column 'Continent' does not exist

Problem background:

A Java application encountered an error when querying the database that the column "Continent" did not exist in a specific table, despite confirming that the column existed in pgAdmin 4. The query attempts to select non-null values ​​from this column.

Problem Diagnosis:

• Verified via pgAdmin 4 that the column "Continent" does exist in the "network.countries" table.
• The query shows that the application obtains column and table names correctly, excluding spelling or semantic errors.
• The error message implies that the column names may need to be referenced using a different schema or table.

Solution:

Fix this issue by surrounding the column names in double quotes in the query:

<code class="language-sql">SELECT "Continent"
FROM network.countries
...</code>

PostgreSQL requires that column names must be enclosed in double quotes when they contain special characters or conflict with keywords. In this case, "Continent" is a reserved keyword in PostgreSQL, so it needs to be enclosed in quotes.

Additional notes:

• Running the query directly in pgAdmin 4 may not encounter the same error, as the interface handles quotes automatically.
• Using "countries.Continent" in the query may also work, but this introduces a dependency on the "countries" pattern. Wrapping the column names in double quotes provides a more general solution that works regardless of the schema the table is in.

The above is the detailed content of Why Does My PostgreSQL Query Fail with 'Column \'Continent\' Does Not Exist' Despite the Column Existing?. For more information, please follow other related articles on the PHP Chinese website!