Sql 按表分组，然后将另一个表计数添加到第一个表分组计数中

我想按第一个表分组，然后将第二个和第三个表的结果与分组计数相加。。。但是使用虚拟服务代码

select servicecode, Count(*) as count from servicerequest
    where To_Char(CREATEDATE,'YYYY') = 2018
    and status = 50
    group by servicecode

        union

    select Count(*) as count from CERTREQUEST
     WHERE to_char(REQDATE,'yyyy') = 2018
    and service = 1

        union

    select Count(*) as count from LTR
     WHERE to_char(REQDATE,'yyyy') = 2018
    and Service = 1

---

只需在以下两个查询中选择它：

select servicecode, Count(*) as count from servicerequest
    where To_Char(CREATEDATE,'YYYY') = 2018
    and status = 50
    group by servicecode

        union

    select 1, Count(*) as count from CERTREQUEST
     WHERE to_char(REQDATE,'yyyy') = 2018
    and service = 1

        union

    select 2, Count(*) as count from LTR
     WHERE to_char(REQDATE,'yyyy') = 2018
    and Service = 1

---

使参数编号相同我使用emty字符串，因为我假设

servicecode

是varchar，根据数据类型将值放在这里

select servicecode, Count(*) as count from servicerequest
    where To_Char(CREATEDATE,'YYYY') = 2018
    and status = 50
    group by servicecode

        union all

    select '', Count(*) as count from CERTREQUEST
     WHERE to_char(REQDATE,'yyyy') = 2018
    and service = 1

        union all

    select '',Count(*) as count from LTR
     WHERE to_char(REQDATE,'yyyy') = 2018
    and Service = 1

---

我更喜欢union all

只是一个小的点（太小了，我无法编辑）-在第三个查询中，

''计数（*）

之间缺少一个逗号。还值得一提的是，

UNION-ALL

保留重复的行，而

UNION

将聚合它们。OP可能没有意识到这一点。欢迎访问SO。我建议你阅读这篇文章，因为它为新手提供了非常有用的关于如何写问题的信息。质量问题帮助我们为您提供高质量的答案-我了解您想要实现的目标，但您在使用SQL脚本时遇到的问题是什么？