mysql-查询不同列的数量合计

车辆违规信息表testmodel_test

表结构：

表字段：cra_id（车牌号），if_weigui(该次行驶是否违规，0是正常，1是违规)

目的：

查询表中共有几辆车，违规的有几辆车；

方法1

SELECT COUNT(f.cra_id) carNum, SUM(f.weigui) weiguiNum FROM
(SELECT a.cra_id,b.weigui
FROM testmodel_test a
LEFT JOIN
(SELECT t.cra_id, 1 AS weigui FROM testmodel_test t
WHERE t.if_weigui=1
GROUP BY t.cra_id) b ON b.cra_id=a.cra_id
GROUP BY a.cra_id)f

方法2

SELECT table1.车辆数,table2.违规车辆数 FROM
(SELECT COUNT(DISTINCT(cra_id)) AS '车辆数' FROM `testmodel_test` )table1
JOIN
(SELECT COUNT(DISTINCT(cra_id)) AS '违规车辆数' FROM `testmodel_test` WHERE if_weigui=1)table2

如果是有多行数据，可以加个链接控制

SELECT table1.车辆数,table2.违规车辆数 FROM
(SELECT 0 AS a,COUNT(DISTINCT(cra_id)) AS '车辆数' FROM `testmodel_test` )table1
JOIN
(SELECT 0 AS c ,COUNT(DISTINCT(cra_id)) AS '违规车辆数' FROM `testmodel_test` WHERE if_weigui=1)table2
ON table1.a=table2.c

结果：