private static bool ContainsTable(ISqlTableSource table, IQueryElement sql)
{
return(null !=
QueryVisitor.FindFirstOrDefault <IQueryExpression>(
sql,
e =>
e == table ||
e.ElementType == EQueryElementType.SqlField && table == ((ISqlField)e).Table ||
e.ElementType == EQueryElementType.Column && table == ((IColumn)e).Parent));
}
private static bool CheckColumn(IColumn column, IQueryExpression expr, ISelectQuery query, bool optimizeValues,
bool optimizeColumns)
{
if (expr is ISqlField || expr is IColumn || expr is ISqlParameter)
{
return(false);
}
var sqlValue = expr as ISqlValue;
if (sqlValue != null)
{
return(!optimizeValues && 1.Equals(sqlValue.Value));
}
var sqlBinaryExpression = expr as ISqlBinaryExpression;
if (sqlBinaryExpression != null)
{
var e = sqlBinaryExpression;
var expr1 = e.Expr1 as ISqlValue;
if (e.Operation == "*" && expr1 != null)
{
if (expr1.Value is int && (int)expr1.Value == -1)
{
return(CheckColumn(column, e.Expr2, query, optimizeValues, optimizeColumns));
}
}
}
if (optimizeColumns && QueryVisitor.FindFirstOrDefault <ISelectQuery>(expr, IsAggregationFunction) == null)
{
var q = query.ParentSelect ?? query;
var count = QueryVisitor.FindOnce <IColumn>(q).Count(e => e == column);
return(count > 2);
}
return(true);
}
