Can't execute query

insert into web_download_count 
                           set 
                                lang_type      = 'tw', 
                                file_id        = 228,
                                p_name         = 'Brook Headset ',
                                dc_id          = ,
                                dc_name        = '������',
                                IP_address     = '54.163.14.144',
                                user_device    = 0,
                                user_info      = 'claudebot',
                                o_name         = 'Headset_quick guide_220922.pdf',
                                ser_name       = '2209297586.pdf',
                                sport          = 0,
                                version        = '',
                                download_type  = 1,
                                download_time  = '2024-03-29 10:28:44'

MySQL Error: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ' dc_name = '������', ' at line 6

This script cannot continue, terminating.