public override QueryNode VisitSelectQuery(SelectQuery query)
{
PushQueryScope(query.QueryScope);
// Validate all embedded AST entries that need to check a query context.
_queryNestingLevel++;
QueryNode result = base.VisitSelectQuery(query);
_queryNestingLevel--;
// Validate DISTINCT
if (query.IsDistinct)
{
// Ensure that all column sources are datatypes that are comparable.
foreach (SelectColumn columnSource in query.SelectColumns)
{
if (!CheckIfTypeIsComparable(columnSource.Expression.ExpressionType))
{
_errorReporter.InvalidDataTypeInSelectDistinct(columnSource.Expression.ExpressionType);
}
}
}
// Validate TOP
if (query.TopClause != null)
{
if (query.TopClause.WithTies && query.OrderByColumns == null)
{
_errorReporter.TopWithTiesRequiresOrderBy();
}
}
// Ensure that all ORDER BY datatypes are comparable.
if (query.OrderByColumns != null)
{
ValidateOrderByClause(query.OrderByColumns);
}
// Ensure that if both DISTINCT and ORDER BY are presents all expressions in ORDER BY are also part in SELECT.
if (query.IsDistinct && query.OrderByColumns != null)
{
bool allColumnsAreInInput = GetAllColumnsAreInInput(query.SelectColumns, query.OrderByColumns);
if (!allColumnsAreInInput)
{
_errorReporter.OrderByItemsMustBeInSelectListIfDistinctSpecified();
}
}
// Validate GROUP BY and aggregation-only queries.
if (query.GroupByColumns == null)
{
if (query.IsAggregated || query.HavingClause != null)
{
// No grouping applied but at least one aggregation function present. That
// means we have an aggregation-only query.
//
// Check that all expressions in SELECT are either aggregated or do not
// reference any column.
foreach (SelectColumn columnSource in query.SelectColumns)
{
foreach (ColumnRefBinding referencedColumn in AstUtil.GetUngroupedAndUnaggregatedColumns(null, columnSource.Expression))
{
if (referencedColumn.Scope == query.QueryScope)
{
// The column is not an outer reference so this is an error.
_errorReporter.SelectExpressionNotAggregatedAndNoGroupBy(referencedColumn);
}
}
}
// Check that all expressions in HAVING are either aggregated or do not
// reference any column.
if (query.HavingClause != null)
{
foreach (ColumnRefBinding referencedColumn in AstUtil.GetUngroupedAndUnaggregatedColumns(null, query.HavingClause))
{
if (referencedColumn.Scope == query.QueryScope)
{
// The column is not an outer reference so this is an error.
_errorReporter.HavingExpressionNotAggregatedOrGrouped(referencedColumn);
}
}
}
// Check that all expressions in ORDER BY are either aggregated or do not
// reference any column.
if (query.OrderByColumns != null)
{
foreach (OrderByColumn orderByColumn in query.OrderByColumns)
{
foreach (ColumnRefBinding referencedColumn in AstUtil.GetUngroupedAndUnaggregatedColumns(null, orderByColumn.Expression))
{
if (referencedColumn.Scope == query.QueryScope)
{
// The column is not an outer reference so this is an error.
_errorReporter.OrderByExpressionNotAggregatedAndNoGroupBy(referencedColumn);
}
}
}
}
}
}
else
{
// Grouped query:
//
// 1. All expression in GROUP BY must have a datatype that is comparable.
//
// 2. All expressions in GROUP BY must not be aggregated
//
// 3. All expressions in SELECT, ORDER BY, and HAVING must be aggregated, grouped or must not reference
// columns.
// Check that all GROUP BY expressions are not aggregated.
foreach (ExpressionNode groupExpression in query.GroupByColumns)
{
if (!CheckIfTypeIsComparable(groupExpression.ExpressionType))
{
_errorReporter.InvalidDataTypeInGroupBy(groupExpression.ExpressionType);
}
MetaInfo metaInfo = AstUtil.GetMetaInfo(groupExpression);
if (metaInfo.ColumnDependencies.Length == 0)
{
_errorReporter.GroupByItemDoesNotReferenceAnyColumns();
}
}
// Check that all expressions in SELECT are either part of the GROUP BY or are referencing only those
// columns that are part of the GROUP BY.
foreach (SelectColumn columnSource in query.SelectColumns)
{
foreach (ColumnRefBinding referencedColumn in AstUtil.GetUngroupedAndUnaggregatedColumns(query.GroupByColumns, columnSource.Expression))
{
if (referencedColumn.Scope == query.QueryScope)
{
// The column is not an outer reference so this is an error.
_errorReporter.SelectExpressionNotAggregatedOrGrouped(referencedColumn);
}
}
}
// Check that all expressions in HAVING are either part of the GROUP BY or are referencing only those
// columns that are part of the GROUP BY.
if (query.HavingClause != null)
{
foreach (ColumnRefBinding referencedColumn in AstUtil.GetUngroupedAndUnaggregatedColumns(query.GroupByColumns, query.HavingClause))
{
if (referencedColumn.Scope == query.QueryScope)
{
// The column is not an outer reference so this is an error.
_errorReporter.HavingExpressionNotAggregatedOrGrouped(referencedColumn);
}
}
}
// Check that all expressions in the ORDER BY clause are either part of the GROUP BY or are
// referencing only those columns that are part of the GROUP BY.
if (query.OrderByColumns != null)
{
foreach (OrderByColumn orderByColumn in query.OrderByColumns)
{
foreach (ColumnRefBinding referencedColumn in AstUtil.GetUngroupedAndUnaggregatedColumns(query.GroupByColumns, orderByColumn.Expression))
{
if (referencedColumn.Scope == query.QueryScope)
{
// The column is not an outer reference so this is an error.
_errorReporter.OrderByExpressionNotAggregatedOrGrouped(referencedColumn);
}
}
}
}
}
PopQueryScope();
return(result);
}