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drop table if exists t1,t2;
create table t1 (a int, b int, v int as (a+1), index idx(b));
insert into t1(a, b) values
(4, 40), (3, 30), (5, 50), (7, 70), (8, 80), (2, 20), (1, 10);
select * from t1 order by b;
a b v
1 10 2
2 20 3
3 30 4
4 40 5
5 50 6
7 70 8
8 80 9
delete from t1 where v > 6 order by b limit 1;
select * from t1 order by b;
a b v
1 10 2
2 20 3
3 30 4
4 40 5
5 50 6
8 80 9
update t1 set a=v order by b limit 1;
select * from t1 order by b;
a b v
2 10 3
2 20 3
3 30 4
4 40 5
5 50 6
8 80 9
drop table t1;
CREATE TABLE t1 (
a int NOT NULL DEFAULT '0',
v double AS ((1, a)) VIRTUAL
);
ERROR HY000: Expression for computed column cannot return a row
CREATE TABLE t1 (
a CHAR(255) BINARY NOT NULL DEFAULT 0,
b CHAR(255) BINARY NOT NULL DEFAULT 0,
v CHAR(255) BINARY AS (CONCAT(a,b)) VIRTUAL );
INSERT INTO t1(a,b) VALUES ('4','7'), ('4','6');
SELECT 1 AS C FROM t1 ORDER BY v;
C
1
1
DROP TABLE t1;
CREATE TABLE t1(a int, b int DEFAULT 0, v INT AS (b+10) PERSISTENT);
INSERT INTO t1(a) VALUES (1);
SELECT b, v FROM t1;
b v
0 10
DROP TABLE t1;
CREATE TABLE t1(a int DEFAULT 100, v int AS (a+1) PERSISTENT);
INSERT INTO t1 () VALUES ();
CREATE TABLE t2(a int DEFAULT 100 , v int AS (a+1));
INSERT INTO t2 () VALUES ();
SELECT a, v FROM t1;
a v
100 101
SELECT a, v FROM t2;
a v
100 101
DROP TABLE t1,t2;
CREATE TABLE t1 (
a datetime NOT NULL DEFAULT '2000-01-01',
v boolean AS (a < '2001-01-01')
);
INSERT INTO t1(a) VALUES ('2002-02-15');
INSERT INTO t1(a) VALUES ('2000-10-15');
SELECT a, v FROM t1;
a v
2002-02-15 00:00:00 0
2000-10-15 00:00:00 1
SELECT a, v FROM t1;
a v
2002-02-15 00:00:00 0
2000-10-15 00:00:00 1
CREATE TABLE t2 (
a datetime NOT NULL DEFAULT '2000-01-01',
v boolean AS (a < '2001-01-01') PERSISTENT
);
INSERT INTO t2(a) VALUES ('2002-02-15');
INSERT INTO t2(a) VALUES ('2000-10-15');
SELECT * FROM t2;
a v
2002-02-15 00:00:00 0
2000-10-15 00:00:00 1
DROP TABLE t1, t2;
CREATE TABLE t1 (
a char(255), b char(255), c char(255), d char(255),
v char(255) AS (CONCAT(c,d) ) VIRTUAL
);
INSERT INTO t1(a,b,c,d) VALUES ('w','x','y','z'), ('W','X','Y','Z');
SELECT v FROM t1 ORDER BY CONCAT(a,b);
v
yz
YZ
DROP TABLE t1;
CREATE TABLE t1 (f1 INTEGER, v1 INTEGER AS (f1) VIRTUAL);
CREATE TABLE t2 AS SELECT v1 FROM t1;
SHOW CREATE TABLE t2;
Table Create Table
t2 CREATE TABLE `t2` (
`v1` int(11) DEFAULT NULL
) ENGINE=MyISAM DEFAULT CHARSET=latin1
DROP TABLE t1,t2;
CREATE TABLE t1 (p int, a double NOT NULL, v double AS (ROUND(a,p)) VIRTUAL);
INSERT INTO t1 VALUES (0,1,0);
Warnings:
Warning 1647 The value specified for computed column 'v' in table 't1' ignored
INSERT INTO t1 VALUES (NULL,0,0);
Warnings:
Warning 1647 The value specified for computed column 'v' in table 't1' ignored
SELECT a, p, v, ROUND(a,p), ROUND(a,p+NULL) FROM t1;
a p v ROUND(a,p) ROUND(a,p+NULL)
1 0 1 1 NULL
0 NULL NULL NULL NULL
DROP TABLE t1;
CREATE TABLE t1 (p int, a double NOT NULL);
INSERT INTO t1(p,a) VALUES (0,1);
INSERT INTO t1(p,a) VALUES (NULL,0);
SELECT a, p, ROUND(a,p), ROUND(a,p+NULL) FROM t1;
a p ROUND(a,p) ROUND(a,p+NULL)
1 0 1 NULL
0 NULL NULL NULL
DROP TABLE t1;
CREATE TABLE t1 (a char(32), v char(32) CHARACTER SET ucs2 AS (a) VIRTUAL);
SHOW CREATE TABLE t1;
Table Create Table
t1 CREATE TABLE `t1` (
`a` char(32) DEFAULT NULL,
`v` char(32) CHARACTER SET ucs2 AS (a) VIRTUAL
) ENGINE=MyISAM DEFAULT CHARSET=latin1
DROP TABLE t1;
CREATE TABLE t1 (a int, b int);
CREATE TABLE t2 (a int, b int as (a+1) VIRTUAL);
SELECT table_schema, table_name, column_name, column_type, extra
FROM information_schema.columns WHERE table_name = 't1';
table_schema table_name column_name column_type extra
test t1 a int(11)
test t1 b int(11)
SELECT table_schema, table_name, column_name, column_type, extra
FROM information_schema.columns WHERE table_name = 't2';
table_schema table_name column_name column_type extra
test t2 a int(11)
test t2 b int(11) VIRTUAL
DROP TABLE t1,t2;
create table t1 (
a int not null, b char(2) not null,
c enum('Y','N') as (case when b = 'aa' then 'Y' else 'N' end) persistent
);
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`a` int(11) NOT NULL,
`b` char(2) NOT NULL,
`c` enum('Y','N') AS (case when b = 'aa' then 'Y' else 'N' end) PERSISTENT
) ENGINE=MyISAM DEFAULT CHARSET=latin1
insert into t1(a,b) values (1,'bb'), (2,'aa'), (3,'cc');
select * from t1;
a b c
1 bb N
2 aa Y
3 cc N
create table t2 (
a int, b int,
c set("y","n")
as (if(a=0,if(b=0,('n,n'),('n,y')),if(b=0,('y,n'),('y,y')))) persistent
);
show create table t2;
Table Create Table
t2 CREATE TABLE `t2` (
`a` int(11) DEFAULT NULL,
`b` int(11) DEFAULT NULL,
`c` set('y','n') AS (if(a=0,if(b=0,('n,n'),('n,y')),if(b=0,('y,n'),('y,y')))) PERSISTENT
) ENGINE=MyISAM DEFAULT CHARSET=latin1
insert into t2(a,b) values (7,0), (2,3), (0,1);
select * from t2;
a b c
7 0 y,n
2 3 y
0 1 y,n
drop table t1,t2;
CREATE TABLE t1 (
ts TIMESTAMP,
tsv TIMESTAMP AS (ADDDATE(ts, INTERVAL 1 DAY)) VIRTUAL
) ENGINE=MyISAM;
INSERT INTO t1 (tsv) VALUES (DEFAULT);
INSERT DELAYED INTO t1 (tsv) VALUES (DEFAULT);
FLUSH TABLES;
SELECT COUNT(*) FROM t1;
COUNT(*)
2
DROP TABLE t1;
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