set @front_requirement_keyword_exists := (
  select count(1)
  from information_schema.columns
  where table_schema = database()
    and table_name = 'front_project'
    and column_name = 'requirement_keyword'
);

set @front_requirement_keyword_sql := if(
  @front_requirement_keyword_exists = 0,
  'alter table front_project add column requirement_keyword varchar(1000) default '''' comment ''需求关键词'' after project_desc',
  'select ''front_project.requirement_keyword already exists'''
);

prepare front_requirement_keyword_stmt from @front_requirement_keyword_sql;
execute front_requirement_keyword_stmt;
deallocate prepare front_requirement_keyword_stmt;