derived table and row number addition

pgm_table.go

@@ -2,10 +2,11 @@ package pgm
 
 // Table in database
 type Table struct {
-	Name       string
-	PK         []string
-	FieldCount uint16
-	debug      bool
+	Name         string
+	DerivedTable Query
+	PK           []string
+	FieldCount   uint16
+	debug        bool
 }
 
 // Debug when set true will print generated query string in stdout
@@ -14,6 +15,10 @@ func (t *Table) Debug() Clause {
 	return t
 }
 
+func (t *Table) Field(f string) Field {
+	return Field(t.Name + "." + f)
+}
+
 // Insert table statement
 func (t *Table) Insert() InsertClause {
 	qb := &insertQry{
@@ -30,10 +35,17 @@ func (t *Table) Insert() InsertClause {
 func (t *Table) Select(field ...Field) SelectClause {
 	qb := &selectQry{
 		debug:  t.debug,
-		table:  t.Name,
 		fields: field,
 	}
 
+	if t.DerivedTable != nil {
+		tName, args := t.DerivedTable.Build(true)
+		qb.table = "(" + tName + ") AS " + t.Name
+		qb.args = args
+	} else {
+		qb.table = t.Name
+	}
+
 	return qb
 }