Setting a variable to CAST(NULL as X) set the result type of the variable to X. (Bug #6598)

mysql-test/r/bigint.result:
  Test to show show that the parser threats big longlong values as unsigned
mysql-test/r/user_var.result:
  Test of CAST(NULL as SIGNED/UNSIGNED)
mysql-test/t/bigint.test:
  Test to show show that the parser threats big longlong values as unsigned
mysql-test/t/user_var.test:
  Test of CAST(NULL as SIGNED/UNSIGNED)
sql/item_func.cc:
  Setting a variable to CAST(NULL as X) set the result type of the variable to X. (Bug #6598)
  Setting a variable to NULL doesn't change the old result type.
sql/item_func.h:
  Detect setting a variable to NULL
sql/unireg.cc:
  Safety fix

1 files changed, 10 insertions, 0 deletions

diff --git a/mysql-test/t/bigint.test b/mysql-test/t/bigint.test
index a26b78254e7..99c8a13d0b5 100644
--- a/mysql-test/t/bigint.test
+++ b/mysql-test/t/bigint.test
@@ -104,3 +104,13 @@ t2.value64=t1.value64;
 
 drop table t1, t2;
 
+#
+# Test of CREATE ... SELECT and unsigned integers
+#
+create table t1 select 1 as 'a';
+show create table t1;
+drop table t1;
+create table t1 select 9223372036854775809 as 'a';
+show create table t1;
+select * from t1;
+drop table t1;