sql table columns for deletion

mysql与oracle

char string is fixed-length

var string variable

Modify the table name: rename table1 to table2; (mysql)

                 alter table1 rename to table2（oracle）

 

Add the new name: alter table product (table name) add column product_1 varchar (40) not null, add column product_2; (mysql)

                  alter table product  (表名)   add  (product_1 varchar(40) not null,product_2);(oracle)

 

                  alter table product  (表名)   drop  column product_1,drop column product_2;

                  alter table product  (表名） drop （prodict_1,product_2);

mysql modify the column name to be repeated plus add column, drop column, oracle just add ()