gyrus-dev/frosty/snowflake-create-data-metric-function

Before writing a CREATE DATA METRIC FUNCTION statement:

1. Read references/parameters.md to review all available parameters and their defaults.
2. For each parameter, decide whether the user's request implies a non-default value.
3. Include only the parameters that differ from the default or that the user explicitly requested.
4. Never use CREATE OR REPLACE — always use CREATE DATA METRIC FUNCTION IF NOT EXISTS where supported.
5. The function body must be a deterministic SQL expression that returns a scalar NUMBER; avoid nondeterministic functions such as CURRENT_TIME or RANDOM.
6. The table argument signature must list every column that the expression references; all listed columns must belong to the same table.
7. Mark the function SECURE when the expression logic or column names would reveal sensitive business rules to non-owner roles.
8. Use $$ delimiters for the AS clause when the expression body contains single-quote characters.