What are the default rules used by the parser when parsing built-in function names?

In fact, when the parser encounters a word that is the name of a built-in function, it must determine whether the name represents a function call or a non-expression reference to an identifier. For example Table or column name. Consider the following query -

1. Select sum(salary) from employee;
2. Create table sum (i int);

In the first query, SUM is a reference to the function call and in the second query, it is a reference to the table name.

The parser follows the following rules to distinguish whether their names are used as identifiers in a function call or non-reference context -

• Rule1 - The names When used as a function call in an expression, there must be no spaces between the name and the following characters (bracket characters).
• Rule2 - Instead, use the function name as the identifier, which cannot be followed by parentheses.

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