1 files changed, 26 insertions, 1 deletions

diff --git a/sql/sql_class.h b/sql/sql_class.h
index 4d114852b15..c2903a26a9b 100644
--- a/sql/sql_class.h
+++ b/sql/sql_class.h
@@ -2649,7 +2649,32 @@ public:
   MI_COLUMNDEF *recinfo,*start_recinfo;
   KEY *keyinfo;
   ha_rows end_write_records;
-  uint	field_count,sum_func_count,func_count;
+  /**
+    Number of normal fields in the query, including those referred to
+    from aggregate functions. Hence, "SELECT `field1`,
+    SUM(`field2`) from t1" sets this counter to 2.
+
+    @see count_field_types
+  */
+  uint	field_count; 
+  /**
+    Number of fields in the query that have functions. Includes both
+    aggregate functions (e.g., SUM) and non-aggregates (e.g., RAND).
+    Also counts functions referred to from aggregate functions, i.e.,
+    "SELECT SUM(RAND())" sets this counter to 2.
+
+    @see count_field_types
+  */
+  uint  func_count;  
+  /**
+    Number of fields in the query that have aggregate functions. Note
+    that the optimizer may choose to optimize away these fields by
+    replacing them with constants, in which case sum_func_count will
+    need to be updated.
+
+    @see opt_sum_query, count_field_types
+  */
+  uint  sum_func_count;   
   uint  hidden_field_count;
   uint	group_parts,group_length,group_null_parts;
   uint	quick_group;