vitessio/vitess · error

unsupported multiple columns in sum clause: %v

Error message

unsupported multiple columns in sum clause: %v

What it means

SUM in a vreplication table plan must take exactly one argument. analyzeExpr rejects SUM(a, b) or SUM() with 'unsupported multiple columns in sum clause' because the plan builder stores only a single column reference for the opSum operation.

Source

Thrown at go/vt/vttablet/tabletmanager/vreplication/table_plan_builder.go:503

			// The vstreamer responds with "keyspace_id" as the field name for this request.
			cexpr.expr = &sqlparser.ColName{Name: sqlparser.NewIdentifierCI("keyspace_id")}
			return cexpr, nil
		}
	}
	if expr, ok := aliased.Expr.(sqlparser.AggrFunc); ok {
		if sqlparser.IsDistinct(expr) {
			return nil, fmt.Errorf("unsupported distinct expression usage: %v", sqlparser.String(expr))
		}
		switch fname := expr.AggrName(); fname {
		case "count":
			if _, ok := expr.(*sqlparser.CountStar); !ok {
				return nil, fmt.Errorf("only count(*) is supported: %v", sqlparser.String(expr))
			}
			cexpr.operation = opCount
			return cexpr, nil
		case "sum":
			if len(expr.GetArgs()) != 1 {
				return nil, fmt.Errorf("unsupported multiple columns in sum clause: %v", sqlparser.String(expr))
			}
			innerCol, ok := expr.GetArg().(*sqlparser.ColName)
			if !ok {
				return nil, fmt.Errorf("unsupported non-column name in sum clause: %v", sqlparser.String(expr))
			}
			if !innerCol.Qualifier.IsEmpty() {
				return nil, fmt.Errorf("unsupported qualifier for column: %v", sqlparser.String(innerCol))
			}
			cexpr.operation = opSum
			cexpr.expr = innerCol
			tpb.addCol(innerCol.Name)
			cexpr.references[innerCol.Name.String()] = true
			return cexpr, nil
		}
	}
	err := sqlparser.Walk(func(node sqlparser.SQLNode) (kontinue bool, err error) {
		switch node := node.(type) {
		case *sqlparser.ColName:

View on GitHub (pinned to 01a25a7d17)

Solutions

1. Split into multiple single-argument sums: SUM(a), SUM(b).
2. If you need a+b then sum the result upstream or compute an expression column outside vreplication.
3. Ensure the SUM argument is exactly one unqualified column name (see also non-column and qualifier restrictions).

Example fix

// before
select sum(a, b) as total from t
// after
select sum(a) as sum_a, sum(b) as sum_b from t

// Ensure SUM has exactly one argument before building the plan
func validSumArgCount(e sqlparser.Expr) bool {
    ag, ok := e.(*sqlparser.AliasedExpr)
    if !ok { return true }
    sum, ok := ag.Expr.(*sqlparser.Sum)
    if !ok { return true }
    return len(sum.Args) == 1
}

func isSingleArgSum(n sqlparser.SQLNode) (ok bool) { s, is := n.(*sqlparser.Sum); return is && len(s.Args) == 1 }

When it happens

Trigger: A Materialize/vreplication SELECT containing SUM with zero or more than one argument, e.g. SELECT SUM(a, b) FROM t; analyzeExpr (via analyzeExprs) hits the len(expr.GetArgs()) != 1 branch.

Common situations: Hand-edited materialization queries; users trying to sum multiple columns in one aggregate instead of summing each column separately; copy-paste from spreadsheets-style formulas.

Related errors

• only count(*) is supported: %v
• unsupported non-column name in sum clause: %v
• unsupported aggregation function: %v
• group by expression is not allowed to reference an aggregate
• unsupported subquery: %v

AI-assisted analysis of vitessio/vitess@01a25a7d17 (2026-09-01). Data as JSON: /api/errors/67601139698a0bcd. Report an issue: GitHub.