func (eh *exprHelper) init( expr Expression, types []sqlbase.ColumnType_Kind, evalCtx *parser.EvalContext, ) error { if expr.Expr == "" { return nil } eh.types = types eh.evalCtx = evalCtx eh.vars = parser.MakeIndexedVarHelper(eh, len(types)) var err error eh.expr, err = processExpression(expr, &eh.vars) if err != nil { return err } var p parser.Parser if p.AggregateInExpr(eh.expr, evalCtx.SearchPath) { return errors.Errorf("expression '%s' has aggregate", eh.expr) } return nil }