Fixed bug#14169: type of group_concat() result changed to blob if tmp_table was

used

In a simple queries a result of the GROUP_CONCAT() function was always of 
varchar type.
But if length of GROUP_CONCAT() result is greater than 512 chars and temporary
table is used during select then the result is converted to blob, due to
policy to not to store fields longer than 512 chars in tmp table as varchar
fields.

In order to provide consistent behaviour, result of GROUP_CONCAT() now
will always be converted to blob if it is longer than 512 chars.
Item_func_group_concat::field_type() is modified accordingly.

1 files changed, 35 insertions, 0 deletions

diff --git a/tests/mysql_client_test.c b/tests/mysql_client_test.c
index c265375a263..8ec5bcd6f0c 100644
--- a/tests/mysql_client_test.c
+++ b/tests/mysql_client_test.c
@@ -14841,6 +14841,40 @@ static void test_bug15613()
 }
 
 /*
+  Bug#14169: type of group_concat() result changed to blob if tmp_table was used
+*/
+static void test_bug14169()
+{
+  MYSQL_STMT *stmt;
+  const char *stmt_text;
+  MYSQL_RES *res;
+  MYSQL_FIELD *field;
+  int rc;
+
+  myheader("test_bug14169");
+
+  rc= mysql_query(mysql, "drop table if exists t1");
+  myquery(rc);
+  rc= mysql_query(mysql, "set session group_concat_max_len=1024");
+  myquery(rc);
+  rc= mysql_query(mysql, "create table t1 (f1 int unsigned, f2 varchar(255))");
+  myquery(rc);
+  rc= mysql_query(mysql, "insert into t1 values (1,repeat('a',255)),"
+                         "(2,repeat('b',255))");
+  myquery(rc);
+  stmt= mysql_stmt_init(mysql);
+  stmt_text= "select f2,group_concat(f1) from t1 group by f2";
+  rc= mysql_stmt_prepare(stmt, stmt_text, strlen(stmt_text));
+  myquery(rc);
+  res= mysql_stmt_result_metadata(stmt);
+  field= mysql_fetch_fields(res);
+  if (!opt_silent)
+    printf("GROUP_CONCAT() result type %i", field[1].type);
+  DIE_UNLESS(field[1].type == MYSQL_TYPE_BLOB);
+
+  rc= mysql_query(mysql, "drop table t1");
+  myquery(rc);
+}/*
   Read and parse arguments and MySQL options from my.cnf
 */
 
@@ -15105,6 +15139,7 @@ static struct my_tests_st my_tests[]= {
   { "test_bug16143", test_bug16143 },
   { "test_bug16144", test_bug16144 },
   { "test_bug15613", test_bug15613 },
+  { "test_bug14169", test_bug14169 },
   { 0, 0 }
 };