sql - 具有多个标题和多个计数的 sql 查询

Question

我有一张包含客户任务详细信息的表格（附图）。我想要结果，例如每个客户在特定月份收到的任务数量，不。自开始日期起 5 天内完成的任务及其合规性。有人可以帮忙做一个 SQL 查询吗

client | No.of tasks of a month | No.of tasks completed on time | % of compliance
A      | 5                      | 4                             | 75%

Answer 1

假设您有一个相当新的 sql-server，请尝试这样的事情（根据需要更改表和列的名称）。

select 
    x.Client
,   x.MonthTasks
,   x.CompletedOnTime
,   Compliance = x.CompletedOnTime * 100 / x.MonthTasks
from (
    select 
        t.Client
    ,   MonthTasks = Count(1)
    ,   CompletedOnTime = SUM(CASE WHEN DATEDIFF(day, t.TaskStart, t.TaskEnd)<=5 THEN 1 ELSE 0 END)
    from tasks as t
    where
        year(t.TaskStart) = 2018    -- put year
    and month(t.TaskStart) = 10     -- put month
    group by t.Client
) as x
order by x.Client

Answer 2

关于您的最后一条评论，这是一个最小的、未准备好生产的想法：

假设您有一个组合框，可以显示月份和年份

cbYear.DataSource = new int[] { 2017, 2018, 2019 };
cbMonth.DataSource = new string[] { "Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Ago", "Sep", "Oct", "Nov", "Dec" };

和一个 datagridview dgv，你可以做这样的事情（在一个按钮中）

        SqlConnection con = new SqlConnection("Data Source=(LocalDb)\\MSSQLLocalDB;Initial Catalog=test;Integrated Security=SSPI");
        con.Open();
        SqlCommand cmd = con.CreateCommand();
        cmd.CommandText = @"
select 
    x.Client
,   x.MonthTasks
,   x.CompletedOnTime
,   Compliance = x.CompletedOnTime * 100 / x.MonthTasks
from (
    select 
        t.Client
   ,    MonthTasks = Count(1)
   ,    CompletedOnTime = SUM(CASE WHEN DATEDIFF(day, t.TaskStart, t.TaskEnd)<=5 THEN 1 ELSE 0 END)
   from tasks as t
   where
        year(t.TaskStart) = @year
   and month(t.TaskStart) = @month
   group by t.Client
) as x
order by x.Client
        ";

        cmd.Parameters.AddWithValue("@year", cbYear.SelectedItem);
        cmd.Parameters.AddWithValue("@month", cbMonth.SelectedIndex +1);

        var dr = cmd.ExecuteReader(CommandBehavior.CloseConnection);
        var dt = new DataTable();
        dt.Load(dr);

        dgv.AutoGenerateColumns = true;
        dgv.DataSource = dt;
        dgv.Refresh();

我再说一遍，你必须捕获任何错误，也许在存储过程中转换查询，但这可以作为一个起点。