| Server IP : 45.40.142.9 / Your IP : 216.73.216.250 Web Server : Apache System : Linux s45-40-142-9.secureserver.net 2.6.32-754.35.1.el6.x86_64 #1 SMP Sat Nov 7 12:42:14 UTC 2020 x86_64 User : bayspec ( 506) PHP Version : 5.6.40 Disable Function : NONE MySQL : ON | cURL : ON | WGET : ON | Perl : ON | Python : ON | Sudo : ON | Pkexec : ON Directory : /usr/share/mysql-test/r/ |
Upload File : |
drop table if exists t1,t2;
create table t1(str varchar(10) default 'def',strnull varchar(10),intg int default '10',rel double default '3.14');
insert into t1 values ('','',0,0.0);
select default(str), default(strnull), default(intg), default(rel) from t1;
default(str) default(strnull) default(intg) default(rel)
def NULL 10 3.14
explain extended select default(str), default(strnull), default(intg), default(rel) from t1;
id select_type table type possible_keys key key_len ref rows filtered Extra
1 SIMPLE t1 system NULL NULL NULL NULL 1 100.00 NULL
Warnings:
Note 1003 /* select#1 */ select default('') AS `default(str)`,default('') AS `default(strnull)`,default('0') AS `default(intg)`,default('0') AS `default(rel)` from dual
select * from t1 where str <> default(str);
str strnull intg rel
0 0
explain select * from t1 where str <> default(str);
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 system NULL NULL NULL NULL 1 NULL
drop table t1;
CREATE TABLE t1 (id int(11), s varchar(20));
INSERT INTO t1 VALUES (1, 'one'), (2, 'two'), (3, 'three');
SELECT s, 32 AS mi FROM t1 GROUP BY s HAVING DEFAULT(mi) IS NULL;
ERROR HY000: Field 'mi' doesn't have a default value
DROP TABLE t1;