Function typeCheckTupleComparison

postgres/parser/sem/tree/type_check.go:2233–2258

typeCheckTupleComparison type checks a comparison between two tuples, asserting that the elements of the two tuples are comparable at each index.

(
	ctx context.Context, semaCtx *SemaContext, op ComparisonOperator, left *Tuple, right *Tuple,
)

// typeCheckTupleComparison type checks a comparison between two tuples,
// asserting that the elements of the two tuples are comparable at each index.
func typeCheckTupleComparison(
	ctx context.Context, semaCtx *SemaContext, op ComparisonOperator, left *Tuple, right *Tuple,
) (TypedExpr, TypedExpr, error) {
	// All tuples must have the same length.
	tupLen := len(left.Exprs)
	if err := checkTupleHasLength(right, tupLen); err != nil {
		return nil, nil, err
	}
	left.typ = types.MakeTuple(make([]*types.T, tupLen))
	right.typ = types.MakeTuple(make([]*types.T, tupLen))
	for elemIdx := range left.Exprs {
		leftSubExpr := left.Exprs[elemIdx]
		rightSubExpr := right.Exprs[elemIdx]
		leftSubExprTyped, rightSubExprTyped, _, _, err := typeCheckComparisonOp(ctx, semaCtx, op, leftSubExpr, rightSubExpr)
		if err != nil {
			exps := Exprs([]Expr{left, right})
			return nil, nil, pgerror.Newf(pgcode.DatatypeMismatch, "tuples %s are not comparable at index %d: %s",
				&exps, elemIdx+1, err)
		}
		left.Exprs[elemIdx] = leftSubExprTyped
		left.typ.TupleContents()[elemIdx] = leftSubExprTyped.ResolvedType()
		right.Exprs[elemIdx] = rightSubExprTyped
		right.typ.TupleContents()[elemIdx] = rightSubExprTyped.ResolvedType()
	}
	return left, right, nil
}

// typeCheckSameTypedTupleExprs type checks a list of expressions, asserting
// that all are tuples which have the same type or nulls. The function expects