CREATE TABLE t1(x, y, z);
PRAGMA writable_schema = 1;
CREATE TABLE xyz(a, b, c CHECK (c!="null") );
CREATE INDEX i2 ON t1(x, y, z||"abc");
CREATE INDEX i3 ON t1("w"||"");
CREATE INDEX i4 ON t1(x) WHERE z="w";
INSERT INTO xyz VALUES(1, 2, 3);
INSERT INTO t1 VALUES(1, 2, 3);
INSERT INTO t1 VALUES(4, 5, 'w');
SELECT * FROM t1 WHERE z='w';
SELECT sql FROM sqlite_master;