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 * 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 t1.i 1 7 1 1 0 0 4.0000 2.2361 ENUM('1','3','5','7') NOT NULL t1.j 2 8 1 1 0 0 5.0000 2.2361 ENUM('2','4','6','8') NOT NULL t1.empty_string 0 0 4 0 0.0000 NULL CHAR(0) NOT NULL t1.bool N Y 1 1 0 0 1.0000 NULL ENUM('N','Y') NOT NULL 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 t1.i 1 7 1 1 0 0 4.0000 2.2361 TINYINT(1) UNSIGNED NOT NULL t1.j 2 8 1 1 0 0 5.0000 2.2361 TINYINT(1) UNSIGNED NOT NULL t1.empty_string 0 0 4 0 0.0000 NULL CHAR(0) NOT NULL t1.bool N Y 1 1 0 0 1.0000 NULL ENUM('N','Y') NOT NULL 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 t1.i 1 7 1 1 0 0 4.0000 2.2361 ENUM('1','3','5','7') NOT NULL t1.j 2 8 1 1 0 0 5.0000 2.2361 ENUM('2','4','6','8') NOT NULL t1.empty_string 0 0 4 0 0.0000 NULL CHAR(0) NOT NULL t1.bool N Y 1 1 0 0 1.0000 NULL ENUM('N','Y') NOT NULL 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;