Added mysql_fetch_column function

Added MYSQL_TYPE_NULL as a dummy bind case for fetch buffers
Fix for offset based re-fetch using mysql_fetch_column
Misc cleanups for ODBC compatibility

include/mysql.h

@@ -509,12 +509,15 @@ typedef struct st_mysql_bind
   my_bool       *is_null;	  /* Pointer to null indicators */
   char		*buffer;	  /* buffer to get/put data */
   enum enum_field_types buffer_type;	/* buffer type */
-  /* Must be set for string/blob data */
-  unsigned long buffer_length;		/* buffer length */  
+  unsigned long buffer_length;    /* buffer length, must be set for str/binary */  
 
-  /* The following are for internal use. Set by mysql_bind_param */
+  /* Following are for internal use. Set by mysql_bind_param */
+  unsigned char *inter_buffer;    /* for the current data position */
+  unsigned long offset;           /* offset position for char/binary fetch */
   unsigned int	param_number;	  /* For null count and error messages */
   my_bool	long_data_used;	  /* If used with mysql_send_long_data */
+  my_bool       binary_data;      /* data buffer is binary */
+  my_bool       null_field;       /* NULL data cache flag */
   void (*store_param_func)(NET *net, struct st_mysql_bind *param);
   void (*fetch_result)(struct st_mysql_bind *, unsigned char **row);
 } MYSQL_BIND;
@@ -529,8 +532,11 @@ typedef struct st_mysql_stmt
   MYSQL_BIND	 *bind;	               /* row binding */
   MYSQL_FIELD	 *fields;	       /* prepare meta info */
   LIST           list;                 /* list to keep track of all stmts */
+  unsigned char  *current_row;         /* unbuffered row */
+  unsigned char  *last_fetched_buffer; /* last fetched column buffer */
   char		 *query;	       /* query buffer */
   MEM_ROOT	 mem_root;	       /* root allocations */
+  my_ulonglong   last_fetched_column;  /* last fetched column */
   unsigned long  param_count;	       /* parameters count */
   unsigned long  field_count;	       /* fields count */
   unsigned long	 stmt_id;	       /* Id for prepared statement */
@@ -558,6 +564,9 @@ my_bool STDCALL mysql_commit(MYSQL * mysql);
 my_bool STDCALL mysql_rollback(MYSQL * mysql);
 my_bool STDCALL mysql_autocommit(MYSQL * mysql, my_bool auto_mode);
 int	STDCALL mysql_fetch(MYSQL_STMT *stmt);
+int STDCALL mysql_fetch_column(MYSQL_STMT *stmt, MYSQL_BIND *bind, 
+                               my_ulonglong column, 
+                               unsigned long offset);
 my_bool STDCALL mysql_send_long_data(MYSQL_STMT *stmt, 
 				     unsigned int param_number,
 				     const char *data, 

libmysql/libmysql.def

@@ -112,13 +112,22 @@ EXPORTS
 	mysql_param_count
         mysql_bind_param
         mysql_bind_result
+	mysql_param_result
         mysql_prepare_result
         mysql_stmt_close
         mysql_stmt_error
         mysql_stmt_errno
         mysql_fetch
+	mysql_fetch_column
         mysql_send_long_data
         mysql_next_result
+	mysql_stmt_affected_rows
+	mysql_stmt_store_result
+	mysql_stmt_data_seek
+	mysql_stmt_row_seek
+	mysql_stmt_row_tell
+	mysql_stmt_num_rows
+	mysql_more_results
         mysql_commit
         mysql_rollback
         mysql_autocommit