mySQL unexpected syntax error with "DECIMAL" -


this 5th day learning sql on mysql.

i don't understand why system tells me following error.

my code is:

create table elements( name varchar(20), symbol varchar(2) primary key, atomicnumber tinyint,  atomicmass dec(4,2)     -- ending doesn't need ,  similar sas );  insert elements values ('actinium','ac',89,227); -- here want modify field type of existing table because aluminum has decimal #'s in mass  alter table elements modify atomicmass decimal(9,3);   -- q:   not understand why syntax error.

system message: "syntax error: unexpected 'decimal(decimal)'" runs , changes field constraint error message still there.

additional question(utterly noob question,please tolerate me): how put 'space' in name of column? i'm using "atomicnumber" want "atomic number."

thanks! :)

consult https://dev.mysql.com/doc/refman/5.6/en/alter-table.html.

you missing column. 

alter table elements modify column `atomicmass` decimal(9,3);

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