DROP TABLE IF EXISTS t1;
CREATE TABLE t1 ( number INT NOT NULL, alpha CHAR(6) NOT NULL );
INSERT INTO t1 VALUES (1413006,'idlfmv'),
(1413065,'smpsfz'),(1413127,'sljrhx'),(1413304,'qerfnd');
SELECT number, alpha, CONCAT_WS('<---->',number,alpha) AS new
FROM t1 GROUP BY number;
number	alpha	new
1413006	idlfmv	1413006<---->idlfmv
1413065	smpsfz	1413065<---->smpsfz
1413127	sljrhx	1413127<---->sljrhx
1413304	qerfnd	1413304<---->qerfnd
SELECT CONCAT_WS('<---->',number,alpha) AS new
FROM t1 GROUP BY new LIMIT 1;
new
1413006<---->idlfmv
SELECT number, alpha, CONCAT_WS('<->',number,alpha) AS new
FROM t1 GROUP BY new LIMIT 1;
number	alpha	new
1413006	idlfmv	1413006<->idlfmv
SELECT number, alpha, CONCAT_WS('-',number,alpha,alpha,alpha,alpha,alpha,alpha,alpha) AS new
FROM t1 GROUP BY new LIMIT 1;
number	alpha	new
1413006	idlfmv	1413006-idlfmv-idlfmv-idlfmv-idlfmv-idlfmv-idlfmv-idlfmv
SELECT number, alpha, CONCAT_WS('<------------------>',number,alpha) AS new
FROM t1 GROUP BY new LIMIT 1;
number	alpha	new
1413006	idlfmv	1413006<------------------>idlfmv
drop table t1;
create table t1 (a char(4), b double, c date, d tinyint(4));
insert into t1 values ('AAAA', 105, '2003-03-01', 1);
select * from t1 where concat(A,C,B,D) = 'AAAA2003-03-011051';
a	b	c	d
AAAA	105	2003-03-01	1
drop table t1;
select 'a' union select concat('a', -4);
a
a
a-4
select 'a' union select concat('a', -4.5);
a
a
a-4.5
select 'a' union select concat('a', -(4 + 1));
a
a
a-5
select 'a' union select concat('a', 4 - 5);
a
a
a-1
select 'a' union select concat('a', -'3');
a
a
a-3
select 'a' union select concat('a', -concat('3',4));
a
a
a-34
select 'a' union select concat('a', -0);
a
a
a0
select 'a' union select concat('a', -0.0);
a
a
good
select concat((select x from (select 'a' as x) as t1 ),
(select y from (select 'b' as y) as t2 )) from (select 1 union select 2 )
as t3;
concat((select x from (select 'a' as x) as t1 ),
(select y from (select 'b' as y) as t2 ))
ab
ab
