求达人回答一下关于MySQL里列属性更改的问题

ALTER [IGNORE] TABLE tbl_name

alter_specification [, alter_specification] ...

alter_specification:

table_option ...

| ADD [COLUMN] column_definition [FIRST | AFTER col_name ]

| ADD [COLUMN] (column_definition,...)

| ADD {INDEX|KEY} [index_name] [index_type] (index_col_name,...)

| ADD [CONSTRAINT [symbol]]

PRIMARY KEY [index_type] (index_col_name,...)

| ADD [CONSTRAINT [symbol]]

UNIQUE [INDEX|KEY] [index_name] [index_type] (index_col_name,...)

| ADD [FULLTEXT|SPATIAL] [INDEX|KEY] [index_name] (index_col_name,...)

| ADD [CONSTRAINT [symbol]]

FOREIGN KEY [index_name] (index_col_name,...)

[reference_definition]

| ALTER [COLUMN] col_name {SET DEFAULT literal | DROP DEFAULT}

| CHANGE [COLUMN] old_col_name column_definition

[FIRST|AFTER col_name]

| MODIFY [COLUMN] column_definition [FIRST | AFTER col_name]

| DROP [COLUMN] col_name

| DROP PRIMARY KEY

| DROP {INDEX|KEY} index_name

| DROP FOREIGN KEY fk_symbol

| DISABLE KEYS

| ENABLE KEYS

| RENAME [TO] new_tbl_name

| ORDER BY col_name [, col_name] ...

| CONVERT TO CHARACTER SET charset_name [COLLATE collation_name]

| [DEFAULT] CHARACTER SET charset_name [COLLATE collation_name]

| DISCARD TABLESPACE

| IMPORT TABLESPACE

index_col_name:

col_name [(length)] [ASC | DESC]

index_type:

USING {BTREE | HASH}

语句如下：（注意拼写）

ALTER TABLE class

CHANGE no number BIGINT

另外：你把字符型转整型是违规的，尤其是你的这个字段保存了字符，就会导致不兼容。

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