Informix Error -2946: You may not calculate an aggregate on the display-only field name.

Reasons / Common Causes

-2946 fires when an aggregate function (AVG, MIN, MAX, COUNT, TOTAL) is applied to a DISPLAYONLY field — per the official guidance, aggregates can only be performed on fields associated with tables, and those tables must be listed in the opening command of the same control block.

1. An aggregate applied directly to a field marked DISPLAYONLY, per the official guidance — the direct, only cause.

Solutions / Resolution

1. Revise the form specification, and recompile, per the official guidance — apply the aggregate to a table-associated field instead, or remove DISPLAYONLY if the field genuinely needs to participate in the aggregate.

Examples

An aggregate on a named DISPLAYONLY field

ATTRIBUTES
  line_total = subtotal, DISPLAYONLY;

INSTRUCTIONS
  AFTER QUERY OF orders
    LET grand_total = TOTAL(line_total);
  END
END
-- -2946: line_total is DISPLAYONLY

Corrected

ATTRIBUTES
  subtotal = subtotal;

INSTRUCTIONS
  AFTER QUERY OF orders
    LET grand_total = TOTAL(subtotal);
  END
END

Diagnostic Checks

1. Check the field named in the aggregate expression for DISPLAYONLY status, and restructure the calculation to use table-associated fields instead.

Related Errors / Related Topics

• -2945 — its official title text is a site-side duplicate of -2944's title, but its own description covers this same aggregate/DISPLAYONLY restriction, including the additional requirement that the field's table be listed in the control block's opening command.

An aggregate function is applied to a DISPLAYONLY field — apply it to a table-associated field instead.