Bug #31221: Optimizer incorrectly identifies impossible WHERE clause

 No warning was generated when a TIMESTAMP with a non-zero time part
 was converted to a DATE value. This caused index lookup to assume
 that this is a valid conversion and was returning rows that match 
 a comparison between a TIMESTAMP value and a DATE keypart.
 Fixed by generating a warning on such a truncation.

1 files changed, 21 insertions, 4 deletions

diff --git a/sql/field.cc b/sql/field.cc
index e6e4195ba1e..c616f3f8588 100644
--- a/sql/field.cc
+++ b/sql/field.cc
@@ -5282,7 +5282,7 @@ int Field_newdate::store(const char *from,uint len,CHARSET_INFO *cs)
   {
     tmp= l_time.day + l_time.month*32 + l_time.year*16*32;
     if (!error && (ret != MYSQL_TIMESTAMP_DATE) &&
-        thd->count_cuted_fields != CHECK_FIELD_IGNORE)
+        (l_time.hour || l_time.minute || l_time.second || l_time.second_part))
       error= 3;                                 // Datetime was cut (note)
   }
 
@@ -5329,10 +5329,16 @@ int Field_newdate::store(longlong nr, bool unsigned_val)
   else
     tmp= l_time.day + l_time.month*32 + l_time.year*16*32;
 
+  if (!error && l_time.time_type != MYSQL_TIMESTAMP_DATE &&
+      (l_time.hour || l_time.minute || l_time.second || l_time.second_part))
+    error= 3;
+
   if (error)
-    set_datetime_warning(MYSQL_ERROR::WARN_LEVEL_WARN,
-                         error == 2 ? ER_WARN_DATA_OUT_OF_RANGE :
-                         WARN_DATA_TRUNCATED,nr,MYSQL_TIMESTAMP_DATE, 1);
+    set_datetime_warning(error == 3 ? MYSQL_ERROR::WARN_LEVEL_NOTE :
+                         MYSQL_ERROR::WARN_LEVEL_WARN,
+                         error == 2 ? 
+                         ER_WARN_DATA_OUT_OF_RANGE : WARN_DATA_TRUNCATED,
+                         nr,MYSQL_TIMESTAMP_DATE, 1);
 
   int3store(ptr,tmp);
   return error;
@@ -5359,6 +5365,17 @@ int Field_newdate::store_time(MYSQL_TIME *ltime, timestamp_type time_type)
       set_datetime_warning(MYSQL_ERROR::WARN_LEVEL_WARN, WARN_DATA_TRUNCATED,
                            str.ptr(), str.length(), MYSQL_TIMESTAMP_DATE, 1);
     }
+    if (!error && ltime->time_type != MYSQL_TIMESTAMP_DATE &&
+        (ltime->hour || ltime->minute || ltime->second || ltime->second_part))
+    {
+      char buff[MAX_DATE_STRING_REP_LENGTH];
+      String str(buff, sizeof(buff), &my_charset_latin1);
+      make_datetime((DATE_TIME_FORMAT *) 0, ltime, &str);
+      set_datetime_warning(MYSQL_ERROR::WARN_LEVEL_NOTE,
+                           WARN_DATA_TRUNCATED,
+                           str.ptr(), str.length(), MYSQL_TIMESTAMP_DATE, 1);
+      error= 3;
+    }
   }
   else
   {