计算工作日的最佳方法是什么？

Question

我的时间序列数据的文本时间戳格式为

DD.MM.YYYY HH:mm:ss.sss

(

.sss

= ms)。 我从 TEXT 时间戳字段中提取每个组件，并将 ISO 格式的时间戳组成为

YYYY-MM-DD HH:mm:ss.sss

。

我通读了关于 strftime

 函数的文档

，但以下内容不起作用：

CREATE TABLE tickdata (
    DateTime TEXT, -- source format = "DD.MM.YYYY HH:mm:ss.sss"
    class TEXT,
    category TEXT,
    upper INT,
    lower INT,
    diff INT GENERATED ALWAYS AS (upper - lower) STORED,
    gen_year  INT GENERATED ALWAYS AS (SUBSTRING(DateTime, 7, 4)) STORED,
    gen_month INT GENERATED ALWAYS AS (SUBSTRING(DateTime, 4, 2)) STORED,
    gen_day   INT GENERATED ALWAYS AS (SUBSTRING(DateTime, 1, 2)) STORED,
    gen_wkd   INT GENERATED ALWAYS AS CAST(strftime('%w',DateTime) AS INT) STORED, -- syntax error
--  gen_wkd   INT GENERATED ALWAYS AS strftime('%w',DateTime) STORED,       -- also syntax error
--  gen_wkd   CAST(strftime('%w',DateTime) AS INT) GENERATED ALWAYS STORED, -- also syntax error
    gen_hr    INT GENERATED ALWAYS AS (SUBSTRING(DateTime, 12, 2)) STORED,
    gen_min   INT GENERATED ALWAYS AS (SUBSTRING(DateTime, 15, 2)) STORED,
    gen_sec   INT GENERATED ALWAYS AS (SUBSTRING(DateTime, 18, 2)) STORED,
    gen_ms    INT GENERATED ALWAYS AS (SUBSTRING(DateTime, 21, 3)) STORED,
    gen_ISODate TEXT GENERATED ALWAYS AS (
        FORMAT('%04d', gen_year) || '-' ||
        FORMAT('%02d', gen_month) || '-' ||
        FORMAT('%02d', gen_day) || ' ' ||
        FORMAT('%02d', gen_hr) || ':' ||
        FORMAT('%02d', gen_min) || ':' ||
        FORMAT('%02d', gen_sec) || '.' ||
        FORMAT('%03d', gen_ms) -- format = "YYYY-MM-DD HH:mm:ss.sss"
    ) STORED
);

如何创建一个计算列来存储每行时间戳所属的星期几？

Answer 1

如评论中所示，您需要将括号括起来。

此外，你传递了错误的论点。

gen_wkd INT GENERATED ALWAYS AS (strftime('%w', gen_ISODate)) STORED,

---

多个

format

+ concat 可能只是一次调用，并且通过

explain

输出来判断，这样可能会更有效：

printf('%04d-%02d-%02d %02d:%02d:%02d.%03d',
       gen_year, gen_month, gen_day,
       gen_hr, gen_min, gen_sec, gen_ms)