public void Test_Select()
{
var sql = @"SELECT Customer.firstname, Customer.lastname, Address.Country, City
FROM Customer
INNER JOIN Address ON Address.CustNo = Customer.CustNo";
var visitor = parser.ParseScript(sql);
var selectNode = visitor.SelectNodes.First();
var tableVisitor = new TableVisitor();
selectNode.Accept(tableVisitor);
var tables = tableVisitor.SelectNodes;
Console.WriteLine(
"{0}: {1}",
"Tables",
String.Join(",", tables.Select(x => x.SchemaObject.BaseIdentifier.Value))
);
var columnsVisitor = new ColumnVisitor();
selectNode.Accept(columnsVisitor);
var columns = columnsVisitor.SelectNodes;
Console.WriteLine(
"{0}: {1}",
"Columns",
String.Join(",", columns.Select(x => x))
);
}
protected override Expression VisitMethodCall(MethodCallExpression m)
{
if (m.Method.DeclaringType == typeof(Queryable))
{
if (m.Method.Name == "Where")
{
sb.Append("SELECT * FROM (");
this.Visit(m.Arguments[0]);
sb.Append(") AS T WHERE ");
LambdaExpression lambda = (LambdaExpression)StripQuotes(m.Arguments[1]);
this.Visit(lambda.Body);
return(m);
}
else if (m.Method.Name == "FirstOrDefault")
{
sb.Append("SELECT * FROM (");
this.Visit(m.Arguments[0]);
sb.Append(") AS T WHERE ");
LambdaExpression lambda = (LambdaExpression)StripQuotes(m.Arguments[1]);
this.Visit(lambda.Body);
return(m);
}
else if (m.Method.Name == "Select")
{
LambdaExpression lambda = (LambdaExpression)StripQuotes(m.Arguments[1]);
ColumnProjection projection = new ColumnVisitor().ProjectColumns(lambda.Body, this.row);
sb.Append("SELECT ");
sb.Append(projection.Columns);
sb.Append(" FROM (");
this.Visit(m.Arguments[0]);
sb.Append(") AS T ");
this.projection = projection;
return(m);
}
}
throw new NotSupportedException(string.Format("The method '{0}' is not supported", m.Method.Name));
}
