Fix an edge case for MySQL

- This patch removes auto-generation of queries that have the pattern
  COUNT(tablename.*) which is a syntax error in mysql.

boil/query.go

@@ -151,6 +151,11 @@ func SetLoad(q *Query, relationships ...string) {
 	q.load = append([]string(nil), relationships...)
 }
 
+// SetSelect on the query.
+func SetSelect(q *Query, sel []string) {
+	q.selectCols = sel
+}
+
 // SetCount on the query.
 func SetCount(q *Query) {
 	q.count = true

boil/query_builders.go

@@ -58,7 +58,7 @@ func buildSelectQuery(q *Query) (*bytes.Buffer, []interface{}) {
 		buf.WriteString(strings.Join(selectColsWithAs, ", "))
 	} else if hasSelectCols {
 		buf.WriteString(strings.Join(strmangle.IdentQuoteSlice(q.dialect.LQ, q.dialect.RQ, q.selectCols), ", "))
-	} else if hasJoins {
+	} else if hasJoins && !q.count {
 		selectColsWithStars := writeStars(q)
 		buf.WriteString(strings.Join(selectColsWithStars, ", "))
 	} else {

boil/query_test.go

@@ -290,6 +290,17 @@ func TestFrom(t *testing.T) {
 	}
 }
 
+func TestSetSelect(t *testing.T) {
+	t.Parallel()
+
+	q := &Query{selectCols: []string{"hello"}}
+	SetSelect(q, nil)
+
+	if q.selectCols != nil {
+		t.Errorf("want nil")
+	}
+}
+
 func TestSetCount(t *testing.T) {
 	t.Parallel()
 

templates/03_finishers.tpl

@@ -79,6 +79,7 @@ func (q {{$varNameSingular}}Query) CountP() int64 {
 func (q {{$varNameSingular}}Query) Count() (int64, error) {
   var count int64
 
+  boil.SetSelect(q.Query, nil)
   boil.SetCount(q.Query)
 
   err := boil.ExecQueryOne(q.Query).Scan(&count)