MDEV-4863 COALESCE(time_or_datetime) returns wrong results in numeric context

1 files changed, 80 insertions, 65 deletions

diff --git a/sql/item_cmpfunc.cc b/sql/item_cmpfunc.cc
index e133e2811bd..f0069757ee3 100644
--- a/sql/item_cmpfunc.cc
+++ b/sql/item_cmpfunc.cc
@@ -2374,12 +2374,13 @@ void Item_func_between::print(String *str, enum_query_type query_type)
 void
 Item_func_ifnull::fix_length_and_dec()
 {
-  agg_result_type(&hybrid_type, args, 2);
+  agg_result_type(&cached_result_type, args, 2);
+  cached_field_type= agg_field_type(args, 2);
   maybe_null=args[1]->maybe_null;
   decimals= max(args[0]->decimals, args[1]->decimals);
   unsigned_flag= args[0]->unsigned_flag && args[1]->unsigned_flag;
 
-  if (hybrid_type == DECIMAL_RESULT || hybrid_type == INT_RESULT) 
+  if (cached_result_type == DECIMAL_RESULT || cached_result_type == INT_RESULT) 
   {
     int len0= args[0]->max_length - args[0]->decimals
       - (args[0]->unsigned_flag ? 0 : 1);
@@ -2392,9 +2393,10 @@ Item_func_ifnull::fix_length_and_dec()
   else
     max_length= max(args[0]->max_length, args[1]->max_length);
 
-  switch (hybrid_type) {
+  switch (cached_result_type) {
   case STRING_RESULT:
-    agg_arg_charsets(collation, args, arg_count, MY_COLL_CMP_CONV, 1);
+    if (count_string_result_length(cached_field_type, args, arg_count))
+      return;
     break;
   case DECIMAL_RESULT:
   case REAL_RESULT:
@@ -2407,7 +2409,6 @@ Item_func_ifnull::fix_length_and_dec()
   case IMPOSSIBLE_RESULT:
     DBUG_ASSERT(0);
   }
-  cached_field_type= agg_field_type(args, 2);
 }
 
 
@@ -2421,11 +2422,6 @@ uint Item_func_ifnull::decimal_precision() const
 }
 
 
-enum_field_types Item_func_ifnull::field_type() const 
-{
-  return cached_field_type;
-}
-
 Field *Item_func_ifnull::tmp_table_field(TABLE *table)
 {
   return tmp_table_field_from_field_type(table, 0);
@@ -2499,6 +2495,18 @@ Item_func_ifnull::str_op(String *str)
 }
 
 
+bool Item_func_ifnull::date_op(MYSQL_TIME *ltime, uint fuzzydate)
+{
+  DBUG_ASSERT(fixed == 1);
+  if (!args[0]->get_date(ltime, fuzzydate & ~TIME_FUZZY_DATES))
+    return (null_value= false);
+  if (!args[1]->get_date(ltime, fuzzydate & ~TIME_FUZZY_DATES))
+    return (null_value= false);
+  bzero((char*) ltime,sizeof(*ltime));
+  return null_value= !(fuzzydate & TIME_FUZZY_DATES);
+}
+
+
 /**
   Perform context analysis of an IF item tree.
 
@@ -2587,16 +2595,16 @@ Item_func_if::fix_length_and_dec()
   else
   {
     agg_result_type(&cached_result_type, args+1, 2);
+    cached_field_type= agg_field_type(args + 1, 2);
     if (cached_result_type == STRING_RESULT)
     {
-      if (agg_arg_charsets(collation, args+1, 2, MY_COLL_ALLOW_CONV, 1))
-        return;
+      count_string_result_length(cached_field_type, args + 1, 2);
+      return;
     }
     else
     {
       collation.set(&my_charset_bin);	// Number
     }
-    cached_field_type= agg_field_type(args + 1, 2);
   }
 
   if ((cached_result_type == DECIMAL_RESULT )
@@ -2625,7 +2633,7 @@ uint Item_func_if::decimal_precision() const
 
 
 double
-Item_func_if::val_real()
+Item_func_if::real_op()
 {
   DBUG_ASSERT(fixed == 1);
   Item *arg= args[0]->val_bool() ? args[1] : args[2];
@@ -2635,7 +2643,7 @@ Item_func_if::val_real()
 }
 
 longlong
-Item_func_if::val_int()
+Item_func_if::int_op()
 {
   DBUG_ASSERT(fixed == 1);
   Item *arg= args[0]->val_bool() ? args[1] : args[2];
@@ -2645,7 +2653,7 @@ Item_func_if::val_int()
 }
 
 String *
-Item_func_if::val_str(String *str)
+Item_func_if::str_op(String *str)
 {
   DBUG_ASSERT(fixed == 1);
   Item *arg= args[0]->val_bool() ? args[1] : args[2];
@@ -2658,7 +2666,7 @@ Item_func_if::val_str(String *str)
 
 
 my_decimal *
-Item_func_if::val_decimal(my_decimal *decimal_value)
+Item_func_if::decimal_op(my_decimal *decimal_value)
 {
   DBUG_ASSERT(fixed == 1);
   Item *arg= args[0]->val_bool() ? args[1] : args[2];
@@ -2668,6 +2676,14 @@ Item_func_if::val_decimal(my_decimal *decimal_value)
 }
 
 
+bool Item_func_if::date_op(MYSQL_TIME *ltime, uint fuzzydate)
+{
+  DBUG_ASSERT(fixed == 1);
+  Item *arg= args[0]->val_bool() ? args[1] : args[2];
+  return (null_value= arg->get_date(ltime, fuzzydate));
+}
+
+
 void
 Item_func_nullif::fix_length_and_dec()
 {
@@ -2826,7 +2842,7 @@ Item *Item_func_case::find_item(String *str)
 }
 
 
-String *Item_func_case::val_str(String *str)
+String *Item_func_case::str_op(String *str)
 {
   DBUG_ASSERT(fixed == 1);
   String *res;
@@ -2844,7 +2860,7 @@ String *Item_func_case::val_str(String *str)
 }
 
 
-longlong Item_func_case::val_int()
+longlong Item_func_case::int_op()
 {
   DBUG_ASSERT(fixed == 1);
   char buff[MAX_FIELD_WIDTH];
@@ -2862,7 +2878,7 @@ longlong Item_func_case::val_int()
   return res;
 }
 
-double Item_func_case::val_real()
+double Item_func_case::real_op()
 {
   DBUG_ASSERT(fixed == 1);
   char buff[MAX_FIELD_WIDTH];
@@ -2881,7 +2897,7 @@ double Item_func_case::val_real()
 }
 
 
-my_decimal *Item_func_case::val_decimal(my_decimal *decimal_value)
+my_decimal *Item_func_case::decimal_op(my_decimal *decimal_value)
 {
   DBUG_ASSERT(fixed == 1);
   char buff[MAX_FIELD_WIDTH];
@@ -2901,6 +2917,18 @@ my_decimal *Item_func_case::val_decimal(my_decimal *decimal_value)
 }
 
 
+bool Item_func_case::date_op(MYSQL_TIME *ltime, uint fuzzydate)
+{
+  DBUG_ASSERT(fixed == 1);
+  char buff[MAX_FIELD_WIDTH];
+  String dummy_str(buff, sizeof(buff), default_charset());
+  Item *item= find_item(&dummy_str);
+  if (!item)
+    return (null_value= true);
+  return (null_value= item->get_date(ltime, fuzzydate));
+}
+
+
 bool Item_func_case::fix_fields(THD *thd, Item **ref)
 {
   /*
@@ -2946,7 +2974,10 @@ void Item_func_case::fix_length_and_dec()
   uint found_types= 0;
   if (!(agg= (Item**) sql_alloc(sizeof(Item*)*(ncases+1))))
     return;
-  
+
+  if (else_expr_num == -1 || args[else_expr_num]->maybe_null)
+    maybe_null= 1;
+
   /*
     Aggregate all THEN and ELSE expression types
     and collations when string result
@@ -2959,13 +2990,29 @@ void Item_func_case::fix_length_and_dec()
     agg[nagg++]= args[else_expr_num];
   
   agg_result_type(&cached_result_type, agg, nagg);
-  if ((cached_result_type == STRING_RESULT) &&
-      agg_arg_charsets(collation, agg, nagg, MY_COLL_ALLOW_CONV, 1))
-    return;
-  
   cached_field_type= agg_field_type(agg, nagg);
+
+  if (cached_result_type == STRING_RESULT)
+  {
+    if (count_string_result_length(cached_field_type, agg, nagg))
+      return;
+  }
+  else
+  {
+    max_length= 0;
+    decimals= 0;
+    unsigned_flag= TRUE;
+    for (uint i= 0; i < nagg; i++)
+      agg_num_lengths(agg[i]);
+    if (else_expr_num != -1) 
+      agg_num_lengths(args[else_expr_num]);
+    max_length= my_decimal_precision_to_length(max_length + decimals, decimals,
+                                               unsigned_flag);
+  }
+
+
   /*
-    Aggregate first expression and all THEN expression types
+    Aggregate first expression and all WHEN expression types
     and collations when string comparison
   */
   if (first_expr_num != -1)
@@ -3019,29 +3066,6 @@ void Item_func_case::fix_length_and_dec()
       args[i]->cmp_context= item_cmp_type(left_result_type,
                                           args[i]->result_type());
   }
-
-  if (else_expr_num == -1 || args[else_expr_num]->maybe_null)
-    maybe_null=1;
-  
-  max_length=0;
-  decimals=0;
-  unsigned_flag= TRUE;
-  if (cached_result_type == STRING_RESULT)
-  {
-    for (uint i= 0; i < ncases; i+= 2)
-      agg_str_lengths(args[i + 1]);
-    if (else_expr_num != -1)
-      agg_str_lengths(args[else_expr_num]);
-  }
-  else
-  {
-    for (uint i= 0; i < ncases; i+= 2)
-      agg_num_lengths(args[i + 1]);
-    if (else_expr_num != -1) 
-      agg_num_lengths(args[else_expr_num]);
-    max_length= my_decimal_precision_to_length(max_length + decimals, decimals,
-                                               unsigned_flag);
-  }
 }
 
 
@@ -3149,7 +3173,7 @@ double Item_func_coalesce::real_op()
 }
 
 
-bool Item_func_coalesce::get_date(MYSQL_TIME *ltime,uint fuzzydate)
+bool Item_func_coalesce::date_op(MYSQL_TIME *ltime,uint fuzzydate)
 {
   DBUG_ASSERT(fixed == 1);
   null_value= 0;
@@ -3182,20 +3206,11 @@ my_decimal *Item_func_coalesce::decimal_op(my_decimal *decimal_value)
 void Item_func_coalesce::fix_length_and_dec()
 {
   cached_field_type= agg_field_type(args, arg_count);
-  agg_result_type(&hybrid_type, args, arg_count);
-  Item_result cmp_type;
-  agg_cmp_type(&cmp_type, args, arg_count);
-  ///< @todo let result_type() return TIME_RESULT and remove this special case
-  if (cmp_type == TIME_RESULT)
-  {
-    count_real_length();
-    return;
-  }
-  switch (hybrid_type) {
+  agg_result_type(&cached_result_type, args, arg_count);
+  switch (cached_result_type) {
   case STRING_RESULT:
-    count_only_length();
-    decimals= NOT_FIXED_DEC;
-    agg_arg_charsets(collation, args, arg_count, MY_COLL_ALLOW_CONV, 1);
+    if (count_string_result_length(cached_field_type, args, arg_count))
+      return;          
     break;
   case DECIMAL_RESULT:
     count_decimal_length();
@@ -3204,7 +3219,7 @@ void Item_func_coalesce::fix_length_and_dec()
     count_real_length();
     break;
   case INT_RESULT:
-    count_only_length();
+    count_only_length(args, arg_count);
     decimals= 0;
     break;
   case ROW_RESULT: