cast.result, cast.test:

  Added test case for bug #11283.
field.h, field.cc:
  Fixed bug #11283: wrong conversion from varchar to decimal.
  Added methods Field_string::val_decimal,
  Field_varstring::val_decimal, Field_blob::val_decimal.
  They are not inherited from the base class Field_longstr
  anymore.

mysql-test/r/cast.result

@@ -344,3 +344,11 @@ select cast(s1 as decimal(7,2)) from t1;
 cast(s1 as decimal(7,2))
 111111.00
 drop table t1;
+CREATE TABLE t1 (v varchar(10), tt tinytext, t text,
+mt mediumtext, lt longtext);
+INSERT INTO t1 VALUES ('1.01', '2.02', '3.03', '4.04', '5.05');
+SELECT CAST(v AS DECIMAL), CAST(tt AS DECIMAL), CAST(t AS DECIMAL),
+CAST(mt AS DECIMAL), CAST(lt AS DECIMAL) from t1;
+CAST(v AS DECIMAL)	CAST(tt AS DECIMAL)	CAST(t AS DECIMAL)	CAST(mt AS DECIMAL)	CAST(lt AS DECIMAL)
+1.01	2.02	3.03	4.04	5.05
+DROP TABLE t1;

mysql-test/t/cast.test

@@ -168,3 +168,16 @@ create table t1(s1 time);
 insert into t1 values ('11:11:11');
 select cast(s1 as decimal(7,2)) from t1;
 drop table t1;
+
+#
+# Test for bug #11283: field conversion from varchar, and text types to decimal
+#
+
+CREATE TABLE t1 (v varchar(10), tt tinytext, t text,
+                 mt mediumtext, lt longtext);
+INSERT INTO t1 VALUES ('1.01', '2.02', '3.03', '4.04', '5.05');
+
+SELECT CAST(v AS DECIMAL), CAST(tt AS DECIMAL), CAST(t AS DECIMAL),
+       CAST(mt AS DECIMAL), CAST(lt AS DECIMAL) from t1;
+
+DROP TABLE t1;

sql/field.cc

@@ -5956,14 +5956,6 @@ longlong Field_string::val_int(void)
 }
 
 
-my_decimal *Field_longstr::val_decimal(my_decimal *decimal_value)
-{
-  str2my_decimal(E_DEC_FATAL_ERROR, ptr, field_length, charset(),
-                 decimal_value);
-  return decimal_value;
-}
-
-
 String *Field_string::val_str(String *val_buffer __attribute__((unused)),
 			      String *val_ptr)
 {
@@ -5975,6 +5967,14 @@ String *Field_string::val_str(String *val_buffer __attribute__((unused)),
 }
 
 
+my_decimal *Field_string::val_decimal(my_decimal *decimal_value)
+{
+  str2my_decimal(E_DEC_FATAL_ERROR, ptr, field_length, charset(),
+                 decimal_value);
+  return decimal_value;
+}
+
+
 int Field_string::cmp(const char *a_ptr, const char *b_ptr)
 {
   uint a_len, b_len;
@@ -6288,6 +6288,15 @@ String *Field_varstring::val_str(String *val_buffer __attribute__((unused)),
 }
 
 
+my_decimal *Field_varstring::val_decimal(my_decimal *decimal_value)
+{
+  uint length= length_bytes == 1 ? (uint) (uchar) *ptr : uint2korr(ptr);
+  str2my_decimal(E_DEC_FATAL_ERROR, ptr+length_bytes, length, charset(),
+                 decimal_value);
+  return decimal_value;
+}
+
+
 int Field_varstring::cmp(const char *a_ptr, const char *b_ptr)
 {
   uint a_length, b_length;
@@ -6906,6 +6915,18 @@ String *Field_blob::val_str(String *val_buffer __attribute__((unused)),
 }
 
 
+my_decimal *Field_blob::val_decimal(my_decimal *decimal_value)
+{
+  char *blob;
+  memcpy_fixed(&blob, ptr+packlength, sizeof(char*));
+  if (!blob)
+    blob= "";
+  str2my_decimal(E_DEC_FATAL_ERROR, blob, get_length(ptr), charset(),
+                 decimal_value);
+  return decimal_value;
+}
+
+
 int Field_blob::cmp(const char *a,uint32 a_length, const char *b,
 		    uint32 b_length)
 {

sql/field.h

@@ -381,7 +381,6 @@ public:
                field_name_arg, table_arg, charset)
     {}
 
-  my_decimal *val_decimal(my_decimal *);
   int store_decimal(const my_decimal *d);
 };
 
@@ -993,6 +992,7 @@ public:
   double val_real(void);
   longlong val_int(void);
   String *val_str(String*,String *);
+  my_decimal *val_decimal(my_decimal *);
   int cmp(const char *,const char*);
   void sort_string(char *buff,uint length);
   void sql_type(String &str) const;
@@ -1051,6 +1051,7 @@ public:
   double val_real(void);
   longlong val_int(void);
   String *val_str(String*,String *);
+  my_decimal *val_decimal(my_decimal *);
   int cmp(const char *,const char*);
   void sort_string(char *buff,uint length);
   void get_key_image(char *buff,uint length, imagetype type);
@@ -1106,6 +1107,7 @@ public:
   double val_real(void);
   longlong val_int(void);
   String *val_str(String*,String *);
+  my_decimal *val_decimal(my_decimal *);
   int cmp(const char *,const char*);
   int cmp(const char *a, uint32 a_length, const char *b, uint32 b_length);
   int cmp_binary(const char *a,const char *b, uint32 max_length=~0L);