一、练习数据表my_student_score表结构说明班级高三 1-5 班共 5 个科目语文、数学、英语、物理、化学、生物共 6 个数据量300 条覆盖多班级、多科目适合分组、分页、聚合练习sql-- 表名my_student_score300条完整数据6个班级6个科目分数50-96 DROP TABLE IF EXISTS my_student_score; CREATE TABLE my_student_score ( id INT PRIMARY KEY AUTO_INCREMENT, name VARCHAR(20) NOT NULL, gender CHAR(2) NOT NULL, age INT, class VARCHAR(20), subject VARCHAR(20), score INT, exam_date DATE ); INSERT INTO my_student_score (name, gender, age, class, subject, score, exam_date) VALUES -- 第1组60条2025-01-10高三1-6班6个科目 (陈明宇,男,18,高三1班,语文,85,2025-01-10), (陈明宇,男,18,高三1班,数学,92,2025-01-10), (陈明宇,男,18,高三1班,英语,78,2025-01-10), (陈明宇,男,18,高三1班,物理,88,2025-01-10), (陈明宇,男,18,高三1班,化学,90,2025-01-10), (林雨欣,女,17,高三1班,语文,90,2025-01-10), (林雨欣,女,17,高三1班,数学,88,2025-01-10), (林雨欣,女,17,高三1班,英语,92,2025-01-10), (林雨欣,女,17,高三1班,物理,85,2025-01-10), (林雨欣,女,17,高三1班,生物,89,2025-01-10), (张子豪,男,18,高三2班,语文,76,2025-01-10), (张子豪,男,18,高三2班,数学,95,2025-01-10), (张子豪,男,18,高三2班,物理,82,2025-01-10), (张子豪,男,18,高三2班,化学,87,2025-01-10), (张子豪,男,18,高三2班,生物,80,2025-01-10), (刘思琪,女,17,高三2班,语文,82,2025-01-10), (刘思琪,女,17,高三2班,英语,91,2025-01-10), (刘思琪,女,17,高三2班,物理,79,2025-01-10), (刘思琪,女,17,高三2班,化学,84,2025-01-10), (刘思琪,女,17,高三2班,生物,86,2025-01-10), (黄俊凯,男,19,高三3班,数学,65,2025-01-10), (黄俊凯,男,19,高三3班,英语,70,2025-01-10), (黄俊凯,男,19,高三3班,物理,58,2025-01-10), (黄俊凯,男,19,高三3班,化学,62,2025-01-10), (黄俊凯,男,19,高三3班,生物,55,2025-01-10), (陈雨桐,女,18,高三3班,语文,89,2025-01-10), (陈雨桐,女,18,高三3班,数学,84,2025-01-10), (陈雨桐,女,18,高三3班,英语,87,2025-01-10), (陈雨桐,女,18,高三3班,物理,90,2025-01-10), (陈雨桐,女,18,高三3班,化学,85,2025-01-10), (周浩然,男,17,高三4班,英语,93,2025-01-10), (周浩然,男,17,高三4班,物理,88,2025-01-10), (周浩然,男,17,高三4班,化学,91,2025-01-10), (周浩然,男,17,高三4班,生物,87,2025-01-10), (周浩然,男,17,高三4班,语文,82,2025-01-10), (吴雨菲,女,18,高三4班,数学,79,2025-01-10), (吴雨菲,女,18,高三4班,英语,85,2025-01-10), (吴雨菲,女,18,高三4班,物理,76,2025-01-10), (吴雨菲,女,18,高三4班,化学,80,2025-01-10), (吴雨菲,女,18,高三4班,生物,78,2025-01-10), (郑博文,男,19,高三5班,语文,59,2025-01-10), (郑博文,男,19,高三5班,数学,52,2025-01-10), (郑博文,男,19,高三5班,英语,55,2025-01-10), (郑博文,男,19,高三5班,物理,50,2025-01-10), (郑博文,男,19,高三5班,化学,53,2025-01-10), (王梦瑶,女,17,高三5班,数学,87,2025-01-10), (王梦瑶,女,17,高三5班,英语,90,2025-01-10), (王梦瑶,女,17,高三5班,物理,85,2025-01-10), (王梦瑶,女,17,高三5班,化学,88,2025-01-10), (王梦瑶,女,17,高三5班,生物,83,2025-01-10), (刘天宇,男,18,高三6班,英语,68,2025-01-10), (刘天宇,男,18,高三6班,物理,62,2025-01-10), (刘天宇,男,18,高三6班,化学,65,2025-01-10), (刘天宇,男,18,高三6班,生物,60,2025-01-10), (刘天宇,男,18,高三6班,语文,70,2025-01-10), (陈嘉欣,女,19,高三6班,数学,94,2025-01-10), (陈嘉欣,女,19,高三6班,英语,92,2025-01-10), (陈嘉欣,女,19,高三6班,物理,96,2025-01-10), (陈嘉欣,女,19,高三6班,化学,93,2025-01-10), (陈嘉欣,女,19,高三6班,生物,91,2025-01-10), -- 第2组60条2025-01-11高三1-6班6个科目 (邓子轩,男,18,高三1班,语文,81,2025-01-11), (邓子轩,男,18,高三1班,数学,77,2025-01-11), (邓子轩,男,18,高三1班,英语,90,2025-01-11), (邓子轩,男,18,高三1班,物理,83,2025-01-11), (邓子轩,男,18,高三1班,化学,86,2025-01-11), (冯若曦,女,17,高三1班,语文,85,2025-01-11), (冯若曦,女,17,高三1班,数学,82,2025-01-11), (冯若曦,女,17,高三1班,英语,88,2025-01-11), (冯若曦,女,17,高三1班,物理,90,2025-01-11), (冯若曦,女,17,高三1班,生物,87,2025-01-11), (曹峻熙,男,18,高三2班,英语,73,2025-01-11), (曹峻熙,男,18,高三2班,语文,69,2025-01-11), (曹峻熙,男,18,高三2班,数学,75,2025-01-11), (曹峻熙,男,18,高三2班,物理,71,2025-01-11), (曹峻熙,男,18,高三2班,化学,68,2025-01-11), (彭诗雅,女,17,高三2班,数学,91,2025-01-11), (彭诗雅,女,17,高三2班,英语,85,2025-01-11), (彭诗雅,女,17,高三2班,物理,89,2025-01-11), (彭诗雅,女,17,高三2班,化学,92,2025-01-11), (彭诗雅,女,17,高三2班,生物,88,2025-01-11), (袁弘文,男,19,高三3班,语文,78,2025-01-11), (袁弘文,男,19,高三3班,数学,66,2025-01-11), (袁弘文,男,19,高三3班,物理,59,2025-01-11), (袁弘文,男,19,高三3班,化学,63,2025-01-11), (袁弘文,男,19,高三3班,生物,57,2025-01-11), (吕欣怡,女,18,高三3班,英语,88,2025-01-11), (吕欣怡,女,18,高三3班,语文,92,2025-01-11), (吕欣怡,女,18,高三3班,数学,86,2025-01-11), (吕欣怡,女,18,高三3班,物理,84,2025-01-11), (吕欣怡,女,18,高三3班,化学,90,2025-01-11), (丁俊杰,男,17,高三4班,数学,75,2025-01-11), (丁俊杰,男,17,高三4班,语文,83,2025-01-11), (丁俊杰,男,17,高三4班,英语,79,2025-01-11), (丁俊杰,男,17,高三4班,物理,77,2025-01-11), (丁俊杰,男,17,高三4班,化学,81,2025-01-11), (董婉清,女,18,高三4班,英语,81,2025-01-11), (董婉清,女,18,高三4班,数学,89,2025-01-11), (董婉清,女,18,高三4班,物理,86,2025-01-11), (董婉清,女,18,高三4班,化学,88,2025-01-11), (董婉清,女,18,高三4班,生物,85,2025-01-11), (苏浩然,男,19,高三5班,数学,71,2025-01-11), (苏浩然,男,19,高三5班,英语,76,2025-01-11), (苏浩然,男,19,高三5班,物理,68,2025-01-11), (苏浩然,男,19,高三5班,化学,70,2025-01-11), (苏浩然,男,19,高三5班,生物,65,2025-01-11), (卢雨薇,女,17,高三5班,英语,94,2025-01-11), (卢雨薇,女,17,高三5班,语文,90,2025-01-11), (卢雨薇,女,17,高三5班,数学,92,2025-01-11), (卢雨薇,女,17,高三5班,物理,95,2025-01-11), (卢雨薇,女,17,高三5班,化学,93,2025-01-11), (蒋子豪,男,18,高三6班,语文,67,2025-01-11), (蒋子豪,男,18,高三6班,英语,84,2025-01-11), (蒋子豪,男,18,高三6班,数学,78,2025-01-11), (蒋子豪,男,18,高三6班,物理,75,2025-01-11), (蒋子豪,男,18,高三6班,化学,80,2025-01-11), (蔡雨桐,女,17,高三6班,数学,96,2025-01-11), (蔡雨桐,女,17,高三6班,语文,87,2025-01-11), (蔡雨桐,女,17,高三6班,英语,91,2025-01-11), (蔡雨桐,女,17,高三6班,物理,93,2025-01-11), (蔡雨桐,女,17,高三6班,生物,90,2025-01-11), -- 第3组60条2025-01-12高三1-6班6个科目 (潘俊彦,男,18,高三1班,数学,80,2025-01-12), (潘俊彦,男,18,高三1班,英语,69,2025-01-12), (潘俊彦,男,18,高三1班,物理,72,2025-01-12), (潘俊彦,男,18,高三1班,化学,76,2025-01-12), (潘俊彦,男,18,高三1班,生物,74,2025-01-12), (戴欣悦,女,19,高三1班,语文,93,2025-01-12), (戴欣悦,女,19,高三1班,数学,73,2025-01-12), (戴欣悦,女,19,高三1班,英语,85,2025-01-12), (戴欣悦,女,19,高三1班,物理,80,2025-01-12), (戴欣悦,女,19,高三1班,化学,82,2025-01-12), (宋文轩,男,17,高三2班,英语,82,2025-01-12), (宋文轩,男,17,高三2班,语文,74,2025-01-12), (宋文轩,男,17,高三2班,数学,88,2025-01-12), (宋文轩,男,17,高三2班,物理,86,2025-01-12), (宋文轩,男,17,高三2班,生物,84,2025-01-12), (童梦瑶,女,18,高三2班,语文,88,2025-01-12), (童梦瑶,女,18,高三2班,数学,93,2025-01-12), (童梦瑶,女,18,高三2班,英语,90,2025-01-12), (童梦瑶,女,18,高三2班,物理,92,2025-01-12), (童梦瑶,女,18,高三2班,化学,89,2025-01-12), (秦子昂,男,17,高三3班,英语,75,2025-01-12), (秦子昂,男,17,高三3班,语文,80,2025-01-12), (秦子昂,男,17,高三3班,数学,76,2025-01-12), (秦子昂,男,17,高三3班,物理,78,2025-01-12), (秦子昂,男,17,高三3班,生物,73,2025-01-12), (顾思怡,女,18,高三3班,数学,86,2025-01-12), (顾思怡,女,18,高三3班,英语,95,2025-01-12), (顾思怡,女,18,高三3班,语文,89,2025-01-12), (顾思怡,女,18,高三3班,物理,91,2025-01-12), (顾思怡,女,18,高三3班,化学,94,2025-01-12), (侯博文,男,19,高三4班,语文,71,2025-01-12), (侯博文,男,19,高三4班,数学,79,2025-01-12), (侯博文,男,19,高三4班,英语,65,2025-01-12), (侯博文,男,19,高三4班,物理,68,2025-01-12), (侯博文,男,19,高三4班,化学,63,2025-01-12), (邵雨菲,女,17,高三4班,英语,87,2025-01-12), (邵雨菲,女,17,高三4班,语文,91,2025-01-12), (邵雨菲,女,17,高三4班,数学,85,2025-01-12), (邵雨菲,女,17,高三4班,物理,88,2025-01-12), (邵雨菲,女,17,高三4班,生物,86,2025-01-12), (高子轩,男,18,高三5班,语文,79,2025-01-12), (高子轩,男,18,高三5班,数学,85,2025-01-12), (高子轩,男,18,高三5班,英语,83,2025-01-12), (高子轩,男,18,高三5班,物理,81,2025-01-12), (高子轩,男,18,高三5班,化学,84,2025-01-12), (夏若曦,女,17,高三5班,语文,86,2025-01-12), (夏若曦,女,17,高三5班,数学,90,2025-01-12), (夏若曦,女,17,高三5班,英语,77,2025-01-12), (夏若曦,女,17,高三5班,物理,82,2025-01-12), (夏若曦,女,17,高三5班,生物,80,2025-01-12), (梁峻熙,男,19,高三6班,语文,68,2025-01-12), (梁峻熙,男,19,高三6班,数学,74,2025-01-12), (梁峻熙,男,19,高三6班,英语,80,2025-01-12), (梁峻熙,男,19,高三6班,物理,76,2025-01-12), (梁峻熙,男,19,高三6班,化学,72,2025-01-12), (杜诗雅,女,18,高三6班,语文,92,2025-01-12), (杜诗雅,女,18,高三6班,数学,81,2025-01-12), (杜诗雅,女,18,高三6班,英语,89,2025-01-12), (杜诗雅,女,18,高三6班,物理,87,2025-01-12), (杜诗雅,女,18,高三6班,生物,85,2025-01-12), -- 第4组60条2025-01-13高三1-6班6个科目 (田浩然,男,17,高三1班,语文,75,2025-01-13), (田浩然,男,17,高三1班,数学,94,2025-01-13), (田浩然,男,17,高三1班,英语,66,2025-01-13), (田浩然,男,17,高三1班,物理,80,2025-01-13), (田浩然,男,17,高三1班,化学,78,2025-01-13), (胡雨桐,女,18,高三1班,语文,84,2025-01-13), (胡雨桐,女,18,高三1班,数学,78,2025-01-13), (胡雨桐,女,18,高三1班,英语,92,2025-01-13), (胡雨桐,女,18,高三1班,物理,86,2025-01-13), (胡雨桐,女,18,高三1班,生物,88,2025-01-13), (范子豪,男,19,高三2班,语文,70,2025-01-13), (范子豪,男,19,高三2班,数学,82,2025-01-13), (范子豪,男,19,高三2班,英语,76,2025-01-13), (范子豪,男,19,高三2班,物理,74,2025-01-13), (范子豪,男,19,高三2班,化学,79,2025-01-13), (凌欣悦,女,17,高三2班,语文,94,2025-01-13), (凌欣悦,女,17,高三2班,数学,71,2025-01-13), (凌欣悦,女,17,高三2班,英语,85,2025-01-13), (凌欣悦,女,17,高三2班,物理,83,2025-01-13), (凌欣悦,女,17,高三2班,生物,81,2025-01-13), (耿博文,男,18,高三3班,语文,73,2025-01-13), (耿博文,男,18,高三3班,数学,91,2025-01-13), (耿博文,男,18,高三3班,英语,69,2025-01-13), (耿博文,男,18,高三3班,物理,77,2025-01-13), (耿博文,男,18,高三3班,化学,75,2025-01-13), (毕梦瑶,女,17,高三3班,语文,81,2025-01-13), (毕梦瑶,女,17,高三3班,数学,89,2025-01-13), (毕梦瑶,女,17,高三3班,英语,93,2025-01-13), (毕梦瑶,女,17,高三3班,物理,90,2025-01-13), (毕梦瑶,女,17,高三3班,化学,92,2025-01-13), (戚天宇,男,18,高三4班,语文,65,2025-01-13), (戚天宇,男,18,高三4班,数学,77,2025-01-13), (戚天宇,男,18,高三4班,英语,88,2025-01-13), (戚天宇,男,18,高三4班,物理,82,2025-01-13), (戚天宇,男,18,高三4班,生物,80,2025-01-13), (施嘉欣,女,19,高三4班,语文,87,2025-01-13), (施嘉欣,女,19,高三4班,数学,68,2025-01-13), (施嘉欣,女,19,高三4班,英语,90,2025-01-13), (施嘉欣,女,19,高三4班,物理,85,2025-01-13), (施嘉欣,女,19,高三4班,化学,83,2025-01-13), (车俊彦,男,17,高三5班,语文,78,2025-01-13), (车俊彦,男,17,高三5班,数学,95,2025-01-13), (车俊彦,男,17,高三5班,英语,72,2025-01-13), (车俊彦,男,17,高三5班,物理,84,2025-01-13), (车俊彦,男,17,高三5班,生物,82,2025-01-13), (樊雨菲,女,18,高三5班,语文,91,2025-01-13), (樊雨菲,女,18,高三5班,数学,83,2025-01-13), (樊雨菲,女,18,高三5班,英语,79,2025-01-13), (樊雨菲,女,18,高三5班,物理,88,2025-01-13), (樊雨菲,女,18,高三5班,化学,86,2025-01-13), (焦子昂,男,19,高三6班,语文,74,2025-01-13), (焦子昂,男,19,高三6班,数学,86,2025-01-13), (焦子昂,男,19,高三6班,英语,81,2025-01-13), (焦子昂,男,19,高三6班,物理,79,2025-01-13), (焦子昂,男,19,高三6班,化学,77,2025-01-13), (乐思琪,女,17,高三6班,语文,85,2025-01-13), (乐思琪,女,17,高三6班,数学,76,2025-01-13), (乐思琪,女,17,高三6班,英语,94,2025-01-13), (乐思琪,女,17,高三6班,物理,91,2025-01-13), (乐思琪,女,17,高三6班,生物,89,2025-01-13), -- 第5组60条2025-01-14高三1-6班6个科目 (吉浩然,男,18,高三1班,语文,71,2025-01-14), (吉浩然,男,18,高三1班,数学,80,2025-01-14), (吉浩然,男,18,高三1班,英语,87,2025-01-14), (吉浩然,男,18,高三1班,物理,83,2025-01-14), (吉浩然,男,18,高三1班,化学,85,2025-01-14), (舒雨桐,女,17,高三1班,语文,93,2025-01-14), (舒雨桐,女,17,高三1班,数学,73,2025-01-14), (舒雨桐,女,17,高三1班,英语,82,2025-01-14), (舒雨桐,女,17,高三1班,物理,80,2025-01-14), (舒雨桐,女,17,高三1班,生物,78,2025-01-14), (刁博文,男,19,高三2班,语文,69,2025-01-14), (刁博文,男,19,高三2班,数学,84,2025-01-14), (刁博文,男,19,高三2班,英语,75,2025-01-14), (刁博文,男,19,高三2班,物理,72,2025-01-14), (刁博文,男,19,高三2班,化学,76,2025-01-14), (荣欣悦,女,18,高三2班,语文,89,2025-01-14), (荣欣悦,女,18,高三2班,数学,92,2025-01-14), (荣欣悦,女,18,高三2班,英语,67,2025-01-14), (荣欣悦,女,18,高三2班,物理,86,2025-01-14), (荣欣悦,女,18,高三2班,化学,88,2025-01-14), (向子轩,男,18,高三3班,语文,82,2025-01-14), (向子轩,男,18,高三3班,数学,78,2025-01-14), (向子轩,男,18,高三3班,英语,91,2025-01-14), (向子轩,男,18,高三3班,物理,87,2025-01-14), (向子轩,男,18,高三3班,生物,84,2025-01-14), (晏若曦,女,17,高三3班,语文,77,2025-01-14), (晏若曦,女,17,高三3班,数学,86,2025-01-14), (晏若曦,女,17,高三3班,英语,84,2025-01-14), (晏若曦,女,17,高三3班,物理,81,2025-01-14), (晏若曦,女,17,高三3班,化学,83,2025-01-14), (隋峻熙,男,19,高三4班,语文,80,2025-01-14), (隋峻熙,男,19,高三4班,数学,67,2025-01-14), (隋峻熙,男,19,高三4班,英语,74,2025-01-14), (隋峻熙,男,19,高三4班,物理,70,2025-01-14), (隋峻熙,男,19,高三4班,生物,68,2025-01-14), (狄诗雅,女,18,高三4班,语文,88,2025-01-14), (狄诗雅,女,18,高三4班,数学,93,2025-01-14), (狄诗雅,女,18,高三4班,英语,71,2025-01-14), (狄诗雅,女,18,高三4班,物理,89,2025-01-14), (狄诗雅,女,18,高三4班,化学,91,2025-01-14), (寇浩然,男,17,高三5班,语文,83,2025-01-14), (寇浩然,男,17,高三5班,数学,75,2025-01-14), (寇浩然,男,17,高三5班,英语,90,2025-01-14), (寇浩然,男,17,高三5班,物理,85,2025-01-14), (寇浩然,男,17,高三5班,生物,87,2025-01-14), (广雨桐,女,18,高三5班,语文,72,2025-01-14), (广雨桐,女,18,高三5班,数学,89,2025-01-14), (广雨桐,女,18,高三5班,英语,78,2025-01-14), (广雨桐,女,18,高三5班,物理,82,2025-01-14), (广雨桐,女,18,高三5班,化学,80,2025-01-14), (东子豪,男,19,高三6班,语文,94,2025-01-14), (东子豪,男,19,高三6班,数学,69,2025-01-14), (东子豪,男,19,高三6班,英语,85,2025-01-14), (东子豪,男,19,高三6班,物理,78,2025-01-14), (东子豪,男,19,高三6班,生物,76,2025-01-14), (欧欣悦,女,17,高三6班,语文,74,2025-01-14), (欧欣悦,女,17,高三6班,数学,81,2025-01-14), (欧欣悦,女,17,高三6班,英语,92,2025-01-14), (欧欣悦,女,17,高三6班,物理,90,2025-01-14), (欧欣悦,女,17,高三6班,化学,88,2025-01-14);二、练习题由浅入深一基础查询查询所有学生的姓名、科目、分数。查询所有数据只显示name、subject、score、class四列。查询所有学生的不重复班级。查询所有学生姓名去重显示。查询所有女生的完整信息。二条件查询查询数学成绩大于 90 分的学生姓名和分数。查询语文不及格60的学生信息。查询高三 1 班且性别为男的学生信息。查询英语成绩在 80~95 之间的学生记录。查询姓名包含 “明” 的学生所有信息模糊查询。三排序 分页专项查询所有数学成绩按分数从高到低排序。查询所有学生信息先按班级排序再按分数降序。查询分数最高的前 5 条学生记录。查询所有学生成绩每页显示 10 条查询第 1 页。查询所有学生成绩每页显示 10 条查询第 3 页。查询物理成绩按分数从高到低排序取前 8 名。查询高三 2 班的学生记录每页 15 条查第 2 页。查询所有化学成绩按分数升序查询第 4 页每页 10 条。四聚合函数查询全班数学平均分。查询高三 3 班的总人数。查询英语科目的最高分和最低分。查询所有学生的分数总和。五分组查询按班级分组统计每个班的考试总次数。按科目分组统计每科的平均分。按学生姓名分组查询每个学生的总分。按班级 科目分组统计各班各科的平均分。六分组 HAVING 专项重点难点按班级分组查询平均分数 80 的班级。按科目分组查询最高分 ≥ 90 的科目。按姓名分组查询总分 ≥ 250 的学生。按班级分组查询人数 ≥ 50 的班级。查询语文平均分 80 的班级。查询至少参加 4 门考试并且平均分 ≥ 80 的学生。按科目分组查询该科平均分 85 且最高分 90 的科目。按班级分组查询班级数学平均分 80 的班级。按姓名分组查询学生总分在 240 到 280 之间的学生。按班级 性别分组统计每组人数筛选人数 ≥ 20 的组。七综合练习查询高三 1 班学生的数学成绩按分数降序排列取前 10 名。统计每个班级的英语平均分筛选平均分 85 的班级按平均分降序排列。查询每个学生的总分按总分降序排列取第 2 页每页 5 条。按科目分组统计每科的考试人数、平均分、最高分筛选平均分 80 的科目按考试人数降序排列。三、HAVING 用法总结1. 核心作用HAVING用于在GROUP BY分组后对分组结果进行过滤。2. 与 WHERE 的区别表格关键字作用阶段过滤对象能否使用聚合函数WHERE分组前原始数据行❌ 不能HAVING分组后分组统计结果✅ 必须主要3. 使用场景筛选分组后的统计结果如平均分、总分、人数等。必须结合聚合函数COUNT、SUM、AVG、MAX、MIN或分组字段使用。4. 语法示例sql-- 按班级分组筛选平均分 80 的班级 SELECT class, AVG(score) AS 平均分 FROM my_student_score GROUP BY class HAVING 平均分 80;5. 注意事项HAVING必须跟在GROUP BY之后。若条件不涉及聚合函数优先用WHERE性能更好。四、练习题参考答案部分示例分页查询答案sql-- 14. 第1页每页10条 SELECT * FROM my_student_score LIMIT 0,10; -- 15. 第3页每页10条公式(页数-1)*条数 SELECT * FROM my_student_score LIMIT 20,10;分组 HAVING 答案sql-- 27. 平均分80的班级 SELECT class, AVG(score) AS 平均分 FROM my_student_score GROUP BY class HAVING 平均分 80; -- 32. 至少考4门且平均分≥80的学生 SELECT name, COUNT(*) AS 考试科目数, AVG(score) AS 平均分 FROM my_student_score GROUP BY name HAVING 考试科目数 4 AND 平均分 80;