Fix for bug #7418 "TIMESTAMP not always converted to DATETIME in MAXDB

mode".

Changed grammar rule for "type" token. Now we have one branch with 
optional length specification for TIMESTAMP type instead of two separate
branches.

mysql-test/r/type_timestamp.result

@@ -422,3 +422,13 @@ max(t)
 2004-01-01 01:00:00
 2004-02-01 00:00:00
 drop table t1;
+set sql_mode='maxdb';
+create table t1 (a timestamp, b timestamp(19));
+show create table t1;
+Table	Create Table
+t1	CREATE TABLE "t1" (
+  "a" datetime default NULL,
+  "b" datetime default NULL
+)
+set sql_mode='';
+drop table t1;

mysql-test/t/type_timestamp.test

@@ -286,3 +286,15 @@ insert into t1 values ('a', '2004-01-01 00:00:00'), ('a', '2004-01-01 01:00:00')
                       ('b', '2004-02-01 00:00:00');
 select max(t) from t1 group by a;
 drop table t1;
+
+#
+# Test for bug #7418 "TIMESTAMP not always converted to DATETIME in MAXDB
+# mode". TIMESTAMP columns should be converted DATETIME columns in MAXDB
+# mode regardless of whether a display width is given.
+#
+set sql_mode='maxdb';
+create table t1 (a timestamp, b timestamp(19));
+show create table t1;
+# restore default mode
+set sql_mode='';
+drop table t1;

sql/sql_yacc.yy

@@ -1415,7 +1415,7 @@ type:
 	| YEAR_SYM opt_len field_options { $$=FIELD_TYPE_YEAR; }
 	| DATE_SYM			{ $$=FIELD_TYPE_DATE; }
 	| TIME_SYM			{ $$=FIELD_TYPE_TIME; }
-	| TIMESTAMP
+	| TIMESTAMP opt_len
 	  {
 	    if (YYTHD->variables.sql_mode & MODE_MAXDB)
 	      $$=FIELD_TYPE_DATETIME;
@@ -1428,13 +1428,6 @@ type:
 	      $$=FIELD_TYPE_TIMESTAMP;
             }
 	   }
-	| TIMESTAMP '(' NUM ')'
-          { 
-            LEX *lex= Lex;
-            lex->length= $3.str;
-            lex->type|= NOT_NULL_FLAG;
-            $$= FIELD_TYPE_TIMESTAMP;
-          }
 	| DATETIME			{ $$=FIELD_TYPE_DATETIME; }
 	| TINYBLOB			{ Lex->charset=&my_charset_bin;
 					  $$=FIELD_TYPE_TINY_BLOB; }