数据如今是这种,我想确定出type列中的news和image。。。。甚至以后有其它值,他们分别有多少个。
SELECT type, count(1) AS counts FROM material GROUP BY type
count(1),代表统计第一列。写上1 比写 *的效率高!
数据如今是这种,我想确定出type列中的news和image。。。。甚至以后有其它值,他们分别有多少个。
SELECT type, count(1) AS counts FROM material GROUP BY type