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drop table if exists t1,t2;
create table t1 (i int, j int, empty_string char(10), bool char(1), d date);
insert into t1 values (1,2,"","Y","2002-03-03"), (3,4,"","N","2002-03-04"), (5,6,"","Y","2002-03-04"), (7,8,"","N","2002-03-05");
select count(*) from t1 procedure analyse();
Field_name Min_value Max_value Min_length Max_length Empties_or_zeros Nulls Avg_value_or_avg_length Std Optimal_fieldtype
count(*) 4 4 1 1 0 0 4.0000 0.0000 ENUM('4') NOT NULL
select * from t1 procedure analyse();
Field_name Min_value Max_value Min_length Max_length Empties_or_zeros Nulls Avg_value_or_avg_length Std Optimal_fieldtype
test.t1.i 1 7 1 1 0 0 4.0000 2.2361 ENUM('1','3','5','7') NOT NULL
test.t1.j 2 8 1 1 0 0 5.0000 2.2361 ENUM('2','4','6','8') NOT NULL
test.t1.empty_string 0 0 4 0 0.0000 NULL CHAR(0) NOT NULL
test.t1.bool N Y 1 1 0 0 1.0000 NULL ENUM('N','Y') NOT NULL
test.t1.d 2002-03-03 2002-03-05 10 10 0 0 10.0000 NULL ENUM('2002-03-03','2002-03-04','2002-03-05') NOT NULL
select * from t1 procedure analyse(2);
Field_name Min_value Max_value Min_length Max_length Empties_or_zeros Nulls Avg_value_or_avg_length Std Optimal_fieldtype
test.t1.i 1 7 1 1 0 0 4.0000 2.2361 TINYINT(1) UNSIGNED NOT NULL
test.t1.j 2 8 1 1 0 0 5.0000 2.2361 TINYINT(1) UNSIGNED NOT NULL
test.t1.empty_string 0 0 4 0 0.0000 NULL CHAR(0) NOT NULL
test.t1.bool N Y 1 1 0 0 1.0000 NULL ENUM('N','Y') NOT NULL
test.t1.d 2002-03-03 2002-03-05 10 10 0 0 10.0000 NULL ENUM('2002-03-03','2002-03-04','2002-03-05') NOT NULL
create table t2 select * from t1 procedure analyse();
select * from t2;
Field_name Min_value Max_value Min_length Max_length Empties_or_zeros Nulls Avg_value_or_avg_length Std Optimal_fieldtype
test.t1.i 1 7 1 1 0 0 4.0000 2.2361 ENUM('1','3','5','7') NOT NULL
test.t1.j 2 8 1 1 0 0 5.0000 2.2361 ENUM('2','4','6','8') NOT NULL
test.t1.empty_string 0 0 4 0 0.0000 NULL CHAR(0) NOT NULL
test.t1.bool N Y 1 1 0 0 1.0000 NULL ENUM('N','Y') NOT NULL
test.t1.d 2002-03-03 2002-03-05 10 10 0 0 10.0000 NULL ENUM('2002-03-03','2002-03-04','2002-03-05') NOT NULL
drop table t1,t2;
EXPLAIN SELECT 1 FROM (SELECT 1) a PROCEDURE ANALYSE();
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY <derived2> system NULL NULL NULL NULL 1
2 DERIVED NULL NULL NULL NULL NULL NULL NULL No tables used
create table t1 (a int not null);
create table t2 select * from t1 where 0=1 procedure analyse();
show create table t2;
Table Create Table
t2 CREATE TABLE `t2` (
`Field_name` char(255) NOT NULL default '',
`Min_value` char(255) default NULL,
`Max_value` char(255) default NULL,
`Min_length` bigint(11) NOT NULL default '0',
`Max_length` bigint(11) NOT NULL default '0',
`Empties_or_zeros` bigint(11) NOT NULL default '0',
`Nulls` bigint(11) NOT NULL default '0',
`Avg_value_or_avg_length` char(255) NOT NULL default '',
`Std` char(255) default NULL,
`Optimal_fieldtype` char(64) NOT NULL default ''
) ENGINE=MyISAM DEFAULT CHARSET=latin1
select * from t1 where 0=1 procedure analyse();
Field_name Min_value Max_value Min_length Max_length Empties_or_zeros Nulls Avg_value_or_avg_length Std Optimal_fieldtype
insert into t1 values(1);
drop table t2;
create table t2 select * from t1 where 0=1 procedure analyse();
show create table t2;
Table Create Table
t2 CREATE TABLE `t2` (
`Field_name` char(255) NOT NULL default '',
`Min_value` char(255) default NULL,
`Max_value` char(255) default NULL,
`Min_length` bigint(11) NOT NULL default '0',
`Max_length` bigint(11) NOT NULL default '0',
`Empties_or_zeros` bigint(11) NOT NULL default '0',
`Nulls` bigint(11) NOT NULL default '0',
`Avg_value_or_avg_length` char(255) NOT NULL default '',
`Std` char(255) default NULL,
`Optimal_fieldtype` char(64) NOT NULL default ''
) ENGINE=MyISAM DEFAULT CHARSET=latin1
select * from t2;
Field_name Min_value Max_value Min_length Max_length Empties_or_zeros Nulls Avg_value_or_avg_length Std Optimal_fieldtype
insert into t2 select * from t1 procedure analyse();
select * from t2;
Field_name Min_value Max_value Min_length Max_length Empties_or_zeros Nulls Avg_value_or_avg_length Std Optimal_fieldtype
test.t1.a 1 1 1 1 0 0 1.0000 0.0000 ENUM('1') NOT NULL
insert into t1 values(2);
drop table t2;
create table t2 select * from t1 where 0=1 procedure analyse();
show create table t2;
Table Create Table
t2 CREATE TABLE `t2` (
`Field_name` char(255) NOT NULL default '',
`Min_value` char(255) default NULL,
`Max_value` char(255) default NULL,
`Min_length` bigint(11) NOT NULL default '0',
`Max_length` bigint(11) NOT NULL default '0',
`Empties_or_zeros` bigint(11) NOT NULL default '0',
`Nulls` bigint(11) NOT NULL default '0',
`Avg_value_or_avg_length` char(255) NOT NULL default '',
`Std` char(255) default NULL,
`Optimal_fieldtype` char(64) NOT NULL default ''
) ENGINE=MyISAM DEFAULT CHARSET=latin1
select * from t2;
Field_name Min_value Max_value Min_length Max_length Empties_or_zeros Nulls Avg_value_or_avg_length Std Optimal_fieldtype
insert into t2 select * from t1 procedure analyse();
select * from t2;
Field_name Min_value Max_value Min_length Max_length Empties_or_zeros Nulls Avg_value_or_avg_length Std Optimal_fieldtype
test.t1.a 1 2 1 1 0 0 1.5000 0.5000 ENUM('1','2') NOT NULL
drop table t1,t2;
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