在带有 Postgres 的 Elixir 中，如何生成_series 并从 'UTC' 转换到另一个区域？

Question

我正在尝试创建一个时间序列并将“UTC”时间转换为另一个区域。

我在 Elixir 中有这个代码：

 sd =  ~U[2024-07-31 05:00:00.000000Z]
 ed =  ~U[2024-08-02 04:59:59.000999Z]
 timezone = "US/Central"

 from(
            c in fragment(
              "SELECT generate_series(now() AT TIME ZONE 'UTC' AT TIME ZONE ?, (now() AT TIME ZONE 'UTC' AT TIME ZONE ?) - CAST(? AS INTERVAL), '-1 hour') AS entry",
              ^timezone,
              ^timezone,
              ^%Postgrex.Interval{secs: DateTime.diff(ed, sd)}
            ),
            select: %{
              date_str:
                fragment(
                  "to_char(? AT TIME ZONE ?,'YYYY-MM-DD HH24:MI:SS TZ')",
                  c.entry,
                  ^timezone
                )
            }
          )

我在 utc 而不是我期望的区域中得到这些结果：我想要“US/central”而不是“”或“UTC”

     data: [
        %{date_str: "2024-08-01 16:21:21 "},
        %{date_str: "2024-08-01 15:21:21 "},
        %{date_str: "2024-08-01 14:21:21 "},
        %{date_str: "2024-08-01 13:21:21 "},
        %{date_str: "2024-08-01 12:21:21 "},
        %{date_str: "2024-08-01 11:21:21 "},
        %{date_str: "2024-08-01 10:21:21 "},
        %{date_str: "2024-08-01 09:21:21 "},
        %{date_str: "2024-08-01 08:21:21 "},
        %{date_str: "2024-08-01 07:21:21 "},
        %{date_str: "2024-08-01 06:21:21 "},
        %{date_str: "2024-08-01 05:21:21 "},
        %{date_str: "2024-08-01 04:21:21 "},
        %{date_str: "2024-08-01 03:21:21 "},
        %{date_str: "2024-08-01 02:21:21 "},
        %{date_str: "2024-08-01 01:21:21 "},
        %{date_str: "2024-08-01 00:21:21 "},
        %{date_str: "2024-07-31 23:21:21 "},
        %{date_str: "2024-07-31 22:21:21 "},
        %{date_str: "2024-07-31 21:21:21 "},
        %{date_str: "2024-07-31 20:21:21 "},
        %{date_str: "2024-07-31 19:21:21 "},
        %{date_str: "2024-07-31 18:21:21 "},
        %{date_str: "2024-07-31 17:21:21 "},
        %{date_str: "2024-07-31 16:21:21 "},
        %{date_str: "2024-07-31 15:21:21 "},
        %{date_str: "2024-07-31 14:21:21 "},
        %{date_str: "2024-07-31 13:21:21 "},
        %{date_str: "2024-07-31 12:21:21 "},
        %{date_str: "2024-07-31 11:21:21 "},
        %{date_str: "2024-07-31 10:21:21 "},
        %{date_str: "2024-07-31 09:21:21 "},
        %{date_str: "2024-07-31 08:21:21 "},
        %{date_str: "2024-07-31 07:21:21 "},
        %{date_str: "2024-07-31 06:21:21 "},
        %{date_str: "2024-07-31 05:21:21 "},
        %{date_str: "2024-07-31 04:21:21 "},
        %{date_str: "2024-07-31 03:21:21 "},
        %{date_str: "2024-07-31 02:21:21 "},
        %{date_str: "2024-07-31 01:21:21 "},
        %{date_str: "2024-07-31 00:21:21 "},
        %{date_str: "2024-07-30 23:21:21 "},
        %{date_str: "2024-07-30 22:21:21 "},
        %{date_str: "2024-07-30 21:21:21 "},
        %{date_str: "2024-07-30 20:21:21 "},
        %{date_str: "2024-07-30 19:21:21 "},
        %{date_str: "2024-07-30 18:21:21 "},
        %{date_str: "2024-07-30 17:21:21 "}
      ]

此代码更改导致“utc”

 from(
            c in fragment(
              "SELECT generate_series(now() AT TIME ZONE ?, (now() AT TIME ZONE ?) - CAST(? AS INTERVAL), '-1 hour') AS entry",
              ^timezone,
              ^timezone,
              ^%Postgrex.Interval{secs: DateTime.diff(range.end_date, range.start_date)}
            ),
            select: %{
              date_str:
                fragment(
                  "to_char(? AT TIME ZONE ?,'YYYY-MM-DD HH24:MI:SS TZ')",
             )                   )

新结果：

  %{date_str: "2024-08-01 17:24:22 UTC"},
    %{date_str: "2024-08-01 16:24:22 UTC"},
    %{date_str: "2024-08-01 15:24:22 UTC"},
    %{date_str: "2024-08-01 14:24:22 UTC"},
    %{date_str: "2024-08-01 13:24:22 UTC"},
    %{date_str: "2024-08-01 12:24:22 UTC"},
    %{date_str: "2024-08-01 11:24:22 UTC"},
    %{date_str: "2024-08-01 10:24:22 UTC"},
    %{date_str: "2024-08-01 09:24:22 UTC"},
    %{date_str: "2024-08-01 08:24:22 UTC"},
    %{date_str: "2024-08-01 07:24:22 UTC"},
    %{date_str: "2024-08-01 06:24:22 UTC"},
    %{date_str: "2024-08-01 05:24:22 UTC"},
    %{date_str: "2024-08-01 04:24:22 UTC"},
    %{date_str: "2024-08-01 03:24:22 UTC"},
    %{date_str: "2024-08-01 02:24:22 UTC"},
    %{date_str: "2024-08-01 01:24:22 UTC"},
    %{date_str: "2024-08-01 00:24:22 UTC"},

Answer 1

事实证明，对于“美国/中部”或其他区域的长版本，postgres 中 to_char() 中的 tz 并没有得到很好的支持。 OF [用于偏移] 效果很好。

这对我有用：

from(
            c in fragment(
              "SELECT generate_series(now() AT TIME ZONE ?, (now() AT TIME ZONE ?) - CAST(? AS INTERVAL), '-1 hour') AS entry",
              ^timezone,
              ^timezone,
              ^%Postgrex.Interval{secs: DateTime.diff(range.end_date, range.start_date)}
            ),
            select: %{
              date_str:
                fragment(
                  "to_char(? AT TIME ZONE ?,'YYYY-MM-DD HH12:MI:SS')",
                  c.entry,
                  ^timezone
                )
            }
          )
                                                       )