public ITableInfo VisitUnresolvedGroupReferenceTableInfo(UnresolvedGroupReferenceTableInfo tableInfo)
{
var groupSourceSubStatementTableInfo = tableInfo.ReferencedGroupSource.GetResolvedTableInfo() as ResolvedSubStatementTableInfo;
if (groupSourceSubStatementTableInfo == null)
{
var message = string.Format(
"This SQL generator only supports sequences in from expressions if they are members of an entity or if they come from a GroupBy operator. "
+ "Sequence: '{0}'", tableInfo);
throw new NotSupportedException(message);
}
var groupingSelectExpression = groupSourceSubStatementTableInfo.SqlStatement.SelectProjection as SqlGroupingSelectExpression;
if (groupingSelectExpression == null)
{
throw new NotSupportedException(
"When a sequence retrieved by a subquery is used in a from expression, the subquery must end with a GroupBy operator.");
}
var elementSelectingStatementBuilder = new SqlStatementBuilder(groupSourceSubStatementTableInfo.SqlStatement)
{
GroupByExpression = null
};
var currentKeyExpression = Expression.MakeMemberAccess(
new SqlTableReferenceExpression(tableInfo.ReferencedGroupSource),
groupingSelectExpression.Type.GetProperty("Key"));
var groupKeyJoinCondition = _stage.ResolveWhereExpression(
Expression.OrElse(
Expression.AndAlso(new SqlIsNullExpression(groupingSelectExpression.KeyExpression), new SqlIsNullExpression(currentKeyExpression)),
Expression.AndAlso(
Expression.AndAlso(
new SqlIsNotNullExpression(groupingSelectExpression.KeyExpression),
new SqlIsNotNullExpression(currentKeyExpression)),
Expression.Equal(groupingSelectExpression.KeyExpression, currentKeyExpression))),
_context);
elementSelectingStatementBuilder.AddWhereCondition(groupKeyJoinCondition);
elementSelectingStatementBuilder.SelectProjection = groupingSelectExpression.ElementExpression;
elementSelectingStatementBuilder.RecalculateDataInfo(groupingSelectExpression);
return(new ResolvedJoinedGroupingTableInfo(
_generator.GetUniqueIdentifier("q"),
elementSelectingStatementBuilder.GetSqlStatement(),
groupingSelectExpression,
groupSourceSubStatementTableInfo.TableAlias));
}
protected virtual Expression ResolveWhereCondition(Expression whereCondition)
{
ArgumentUtility.CheckNotNull("whereCondition", whereCondition);
return(_stage.ResolveWhereExpression(whereCondition, _context));
}