INSERTINTO city VALUES(1,'上海',2018,32679,2418);INSERTINTO city VALUES(2,'北京',2018,30320,2171);INSERTINTO city VALUES(3,'深圳',2018,24691,1253);INSERTINTO city VALUES(4,'广州',2018,23000,1450);INSERTINTO city VALUES(5,'重庆',2018,20363,3372);INSERTINTO city VALUES(6,'上海',2019,38155,2424);INSERTINTO city VALUES(7,'北京',2019,35371,2171);INSERTINTO city VALUES(8,'深圳',2019,26927,1302);INSERTINTO city VALUES(9,'广州',2019,23628,1491);INSERTINTO city VALUES(10,'重庆',2019,23605,3372);
COUNT 查询计算2019年一共有多少个城市录入数据(答案 5个)
SELECTCOUNT(*)FROM city WHERE city_year ='2019';
MAX 查询 2018年里 GDP 最高是多少;
SELECTMAX(city_gdp)FROM city WHERE city_year ='2018';
MIN 查询 2018年里 GDP 最低是多少;
SELECTMIN(city_gdp)FROM city WHERE city_year ='2018';
SUM 查询2019年里所有城市 GDP 总和;
SELECTSUM(city_gdp)FROM city WHERE city_year ='2019';
AVG 查询2019年所有城市 GDP 平均值;
SELECTAVG(city_gdp)FROM city WHERE city_year ='2019';