MDEV-7195 AVG() loses precision in INT context

The fix for MDEV-8918 previously fixed the problem reported in MDEV-7195.
Adding a test case from MDEV-7195 only.

Author: Alexander Barkov

mysql-test/r/func_group.result

@@ -2314,5 +2314,22 @@ MIN(a)	SUM(a)	CAST(SUM(a) AS SIGNED)	CAST(AVG(a) AS SIGNED)
 9.223372036854776e18	9.223372036854776e18	9223372036854775807	9223372036854775807
 DROP TABLE t1;
 #
+# MDEV-7195 AVG() loses precision in INT context
+#
+CREATE TABLE t1 (
+auto SERIAL,
+fld1 bigint unsigned NOT NULL,
+companynr tinyint(2) unsigned zerofill DEFAULT '00' NOT NULL,
+UNIQUE fld1 (fld1)
+);
+INSERT INTO t1 VALUES (1,0x7FFFFFFFFFFFFFFF,00);
+INSERT INTO t1 VALUES (2,0x7FFFFFFFFFFFFFFE,37);
+INSERT INTO t1 VALUES (3,0x7FFFFFFFFFFFFFFC,37);
+SELECT companynr, AVG(fld1), AVG(fld1)<<0 AS avg1, CAST(AVG(fld1) AS UNSIGNED)<<0 AS avg2 FROM t1 GROUP BY companynr;
+companynr	AVG(fld1)	avg1	avg2
+00	9223372036854775807.0000	9223372036854775807	9223372036854775807
+37	9223372036854775805.0000	9223372036854775805	9223372036854775805
+DROP TABLE t1;
+#
 # End of 10.1 tests
 #

mysql-test/t/func_group.test

@@ -1593,6 +1593,21 @@ INSERT INTO t1 VALUES (0x7FFFFFFFFFFFFFFF);
 SELECT MIN(a), SUM(a), CAST(SUM(a) AS SIGNED), CAST(AVG(a) AS SIGNED) FROM t1;
 DROP TABLE t1;
 
+--echo #
+--echo # MDEV-7195 AVG() loses precision in INT context
+--echo #
+CREATE TABLE t1 (
+  auto SERIAL,
+  fld1 bigint unsigned NOT NULL,
+  companynr tinyint(2) unsigned zerofill DEFAULT '00' NOT NULL,
+  UNIQUE fld1 (fld1)
+);
+INSERT INTO t1 VALUES (1,0x7FFFFFFFFFFFFFFF,00);
+INSERT INTO t1 VALUES (2,0x7FFFFFFFFFFFFFFE,37);
+INSERT INTO t1 VALUES (3,0x7FFFFFFFFFFFFFFC,37);
+SELECT companynr, AVG(fld1), AVG(fld1)<<0 AS avg1, CAST(AVG(fld1) AS UNSIGNED)<<0 AS avg2 FROM t1 GROUP BY companynr;
+DROP TABLE t1;
+
 --echo #
 --echo # End of 10.1 tests
 --echo #