drop database if exists maskingdb;
create database maskingdb;
use maskingdb;
create table masking (a TEXT, x TEXT, y TEXT);
insert into masking values ("hello", "hello",  "hello");
insert into masking values (NULL,    "hello",  "hello");
insert into masking values ("hello",  NULL,    "hello");
insert into masking values ("hello",  "hello", NULL);
insert into masking values (NULL,     NULL,    "hello");
insert into masking values ("hello",  NULL,    NULL);
insert into masking values (NULL,     NULL,    NULL);
select * from masking;
a	x	y
YYYYY	hello	hello
NULL	hello	hello
YYYYY	NULL	hello
YYYYY	hello	NULL
NULL	NULL	hello
YYYYY	NULL	NULL
NULL	NULL	NULL
drop table masking;
create table masking (x TEXT, a TEXT, y TEXT);
insert into masking values ("hello", "hello", "hello");
insert into masking values (NULL,    "hello",  "hello");
insert into masking values ("hello",  NULL,    "hello");
insert into masking values ("hello",  "hello", NULL);
insert into masking values (NULL,     NULL,    "hello");
insert into masking values ("hello",  NULL,    NULL);
insert into masking values (NULL,     NULL,    NULL);
select * from masking;
x	a	y
hello	YYYYY	hello
NULL	YYYYY	hello
hello	NULL	hello
hello	YYYYY	NULL
NULL	NULL	hello
hello	NULL	NULL
NULL	NULL	NULL
drop table masking;
create table masking (x TEXT, y TEXT, a TEXT);
insert into masking values ("hello", "hello", "hello");
insert into masking values (NULL,    "hello",  "hello");
insert into masking values ("hello",  NULL,    "hello");
insert into masking values ("hello",  "hello", NULL);
insert into masking values (NULL,     NULL,    "hello");
insert into masking values ("hello",  NULL,    NULL);
insert into masking values (NULL,     NULL,    NULL);
select * from masking;
x	y	a
hello	hello	YYYYY
NULL	hello	YYYYY
hello	NULL	YYYYY
hello	hello	NULL
NULL	NULL	YYYYY
hello	NULL	NULL
NULL	NULL	NULL
drop table masking;