There is a table: camera_d, which contains the following fields: mdn comment: model name, md comment: model, ov comment: os version number, rv comment: rom version number, adv comment: Android version number, sdkv comment: SDK version number ,ctry comment: country, prv comment: province, ct comment: city, ctl comment: city level, cty comment: district and county, acid comment: starting user id, u_gd comment: gender, u_ag comment: age, u_ed comment: education, u_mr comment: married, u_cid comment: industry, ts comment: number of startups, drt comment: startup time (unit s), dt comment: date, brd comment: brand, please give sql