Spracherkennung für: .test vermutete Sprache: SQL {SQL[174] VDM[66] VHDL[54]} [Methode: maximale Elemente, drei Dimensionen]
--source include/have_innodb.inc
#
# MDEV-4925 Wrong result - count(distinct), Using index for group-by (scanning)
#
CREATE TABLE t1 (
id int NOT NULL AUTO_INCREMENT,
a int NOT NULL,
b int NOT NULL,
PRIMARY KEY (id),
UNIQUE KEY ba (b, a)
) ENGINE=InnoDB;
INSERT INTO t1 (a, b) VALUES(1,101),(1,102),(1,103),(1,104),(1,105),(1,106),(1,107),(1,108),(1,109),(1,110);
SELECT COUNT(DISTINCT b) FROM t1 WHERE a = 1;
DROP TABLE t1;
[zur Elbe Produktseite wechseln0.14QuellennavigatorsAnalyse erneut starten2026-10-08]
