SET sql_mode=ORACLE;

--echo #
--echo # MDEV-29095 REGEXP_REPLACE treats empty strings different than REPLACE in ORACLE mode
--echo #

#SELECT REGEXP_REPLACE(null,'a','b') ;
#SELECT REGEXP_REPLACE('ab',null,'b') ;
#SELECT REGEXP_REPLACE('ab','a',null) ;
#SELECT REGEXP_REPLACE('ab',null,null) ;

CREATE TABLE t1 (replacement VARCHAR(10));
INSERT INTO t1 VALUES (NULL), ('');
SELECT replacement, REGEXP_REPLACE('abba','a',replacement) FROM t1 ORDER BY replacement;
DROP TABLE t1;

SELECT REGEXP_REPLACE('abba','a',null);
EXPLAIN EXTENDED SELECT REPLACE('abba','a',null) ;

CREATE VIEW v1 AS SELECT REPLACE('abba','a',null) ;
SHOW CREATE VIEW v1;
SELECT * FROM v1;
SET sql_mode=DEFAULT;
SHOW CREATE VIEW v1;
SELECT * FROM v1;
DROP VIEW v1;