Informix Error -947: Declaration of an SPL variable named 'null' conflicts with SQL NULL value.

Reasons / Common Causes

-947 fires when an SPL routine declares a variable literally named null — per the official guidance, this is disallowed because it would restrict the global scope of the NULL constant within the routine.

1. DEFINE null ... (or any declaration using null as the variable's name), per the official guidance — the direct, only cause.
2. A variable name chosen without realizing null can't be shadowed inside an SPL routine — NULL is a reserved word in Informix SQL generally, and this error is the SPL-specific consequence of that: declaring a variable with that name would shadow the global NULL constant within the routine's scope.

Solutions / Resolution

1. Choose a different variable name, per the official guidance — NULL must remain globally available as the SQL null-value constant throughout the routine, so no variable can shadow it.

Examples

The disallowed attempt

CREATE PROCEDURE check_order(p_order_id INT)
  DEFINE null CHAR(10);
  -- -947: 'null' conflicts with the NULL constant
END PROCEDURE;

Corrected

CREATE PROCEDURE check_order(p_order_id INT)
  DEFINE v_status CHAR(10);
END PROCEDURE;

Diagnostic Checks

1. Scan DEFINE statements for a variable literally named null, and rename it.

Related Errors / Related Topics

No closely related error codes are cross-referenced for -947 in this set yet.

null is reserved as a variable name within SPL routines specifically — choose any other name.