优化select e.ygxm as zkysxm, count(*) as total from (select a.ksdm, a.zkys, (select a.ksdm from ms_ghmx where sbxh = a.zkgl) as zkqks from ms_ghmx a where a.ghly = 4 and a.ghsj >= TO_TIMESTAMP('2016-08-01 00:00:00', 'YYYY-MM-DD HH24:MI:SS') AND a.ghsj < TO_TIMESTAMP('2023-05-23 23:59:59', 'YYYY-MM-DD HH24:MI:SS')) b left join gy_ksdm c on b.ksdm = c.ksdm left join gy_ksdm d on b.zkqks = d.ksdm left join gy_ygdm e on b.zkys = e.ygdm group by e.ygxm order by zkysxm

可以考虑以下优化：

1. 尽量避免子查询，可以将子查询的结果存储到临时表中，再进行查询。

2. 使用JOIN代替子查询，因为JOIN通常比子查询更快。

3. 如果可能的话，使用索引来加速JOIN操作。

4. 将WHERE条件中的时间格式转换提前处理，以避免在查询时进行转换。

5. 避免使用通配符（如SELECT *），只选择需要的列。

基于以上优化建议，可以将原查询进行改写：

CREATE TEMPORARY TABLE temp_table AS (
    SELECT 
        a.ksdm, 
        a.zkys, 
        m.zkqks 
    FROM 
        ms_ghmx a 
        LEFT JOIN (
            SELECT 
                sbxh, 
                ksdm AS zkqks 
            FROM 
                ms_ghmx
        ) m ON a.zkgl = m.sbxh 
    WHERE 
        a.ghly = 4 
        AND a.ghsj >= '2016-08-01 00:00:00' 
        AND a.ghsj < '2023-05-23 23:59:59'
);

SELECT 
    e.ygxm AS zkysxm, 
    COUNT(*) AS total 
FROM 
    temp_table t 
    LEFT JOIN gy_ksdm c ON t.ksdm = c.ksdm 
    LEFT JOIN gy_ksdm d ON t.zkqks = d.ksdm 
    LEFT JOIN gy_ygdm e ON t.zkys = e.ygdm 
GROUP BY 
    e.ygxm 
ORDER BY 
    zkysxm;

这个改写可能不是最优解，但可以作为一种参考方案。需要根据实际情况进行调整和优化。