DROP DATABASE IF EXISTS mcs199_db;
CREATE DATABASE mcs199_db;
USE mcs199_db;
CREATE TABLE t1 (x INT, y MEDIUMINT, z CHAR(5))ENGINE=Columnstore;
INSERT INTO t1 VALUES (NULL, NULL, ''),(20, 1, 'aaa'),(39, 2, 'aaa'),(48, 3, 'bbb'),(57, 4, 'bbb'),(66, 5, 'aaa'),(75, 6, 'aaa'),(84, 7, 'bbb');
SELECT REGR_R2(y, x) FROM t1;
REGR_R2(y, x)
0.9814869668246445
SELECT z, REGR_R2(y, x) FROM t1 GROUP BY z ORDER BY z;
z	REGR_R2(y, x)
NULL	NULL
aaa	0.9798973217047071
bbb	1
SELECT REGR_R2(y) FROM t1;
ERROR HY000: Can't initialize function 'regr_r2'; regr_r2() requires two arguments
DROP DATABASE mcs199_db;