Fix for BUG#1547: "SELECT ... WHERE field = var" sometimes give the wrong result in SPs

Two missing methods added to Item_splocal + test case.

mysql-test/r/sp.result

@@ -601,6 +601,27 @@ less	2
 more	17
 delete from t1;
 drop procedure bug1495;
+create procedure bug1547(s char(16))
+begin
+declare x int;
+select data into x from t1 where s = id limit 1;
+if x > 10 then
+insert into t1 values ("less", x-10);
+else
+insert into t1 values ("more", x+10);
+end if;
+end;
+insert into t1 values ("foo", 12), ("bar", 7);
+call bug1547("foo");
+call bug1547("bar");
+select * from t1;
+id	data
+foo	12
+bar	7
+less	2
+more	17
+delete from t1;
+drop procedure bug1547;
 drop table if exists fac;
 create table fac (n int unsigned not null primary key, f bigint unsigned);
 create procedure ifac(n int unsigned)

mysql-test/t/sp.test

@@ -697,6 +697,28 @@ select * from t1|
 delete from t1|
 drop procedure bug1495|
 
+#
+# BUG#1547
+#
+create procedure bug1547(s char(16))
+begin
+  declare x int;
+
+  select data into x from t1 where s = id limit 1;
+  if x > 10 then
+    insert into t1 values ("less", x-10);
+  else
+    insert into t1 values ("more", x+10);
+  end if;
+end|
+
+insert into t1 values ("foo", 12), ("bar", 7)|
+call bug1547("foo")|
+call bug1547("bar")|
+select * from t1|
+delete from t1|
+drop procedure bug1547|
+
 
 #
 # Some "real" examples

sql/item.h

@@ -266,6 +266,16 @@ public:
     this_item()->make_field(field);
   }
 
+  inline Item_result result_type() const
+  {
+    return this_const_item()->result_type();
+  }
+
+  inline bool const_item() const
+  {
+    return FALSE;
+  }
+
 };