Identifiers

Identifiers are used when referencing database objects.

Identifier rules attempt to follow Postgres semantics where possible.

Case-Sensitivity

Identifiers in a SQL query are case-insensitive.

All of the following queries behave exactly the same:

SELECT * FROM CITIES;
SELECT * FROM cities;
SELECT * FROM Cities;

Identifiers wrapped in a double quote (") retain their original casing.

Both of these queries are referencing different tables:

SELECT * FROM "Cities";
SELECT * FROM cities;

Case-insensitivity applies to all database objects, including functions.

Both queries are equivalent:

SELECT abs(-1.0);
SELECT ABS(-1.0);

Generated Column Names

When no explicit alias is provided for an expression in the SELECT list, an column name will be generated using the following rules:

• If an expression is a column reference, the column name is used.
• If an expression is a function, the function name is used.
• If none of the above rules apply, the identifier ?column? is used.