mysql判断字段是否存在的方法

1. desc 命令
格式: desc tablename columnname

例子:
desc `table` `mid`
desc `table` '％abc％'

2. show columns 命令
格式: show columns from tablename like columnname
例子:
show columns from `table` like 'mid'
show columns from `table` like '％abc％'

3. describe 命令
格式: describe tablename columnname
describe 相當于 show columns from
例子:
describe `table` `mid`

describe `table` '％abc％'