在以下查询中,1/2的答案始终为零,而应为0.5。您能告诉我如何将两个int列转换为float/double吗?

SELECT 1/2, total, sb_ondate, likes
  FROM (
      SELECT sb_ondate, COUNT(*) AS total,
             STRFTIME("%w",sb_ondate) AS weekDay,
             COUNT(CASE WHEN sb_reaction = 'like' THEN sb_id END) AS likes
        FROM diet
    GROUP BY weekDay) AS f;

谢谢。

最佳答案

Cast两个除数之一作为real:

SELECT 1 / CAST(2 AS REAL),...

交互式Python session 示例:
>>> import sqlite3
>>> c = sqlite3.connect(':memory:')
>>> c.execute("create table t (a int,b int);")
<sqlite3.Cursor object at 0x7f9b0e9539d0>
>>> c.execute("insert into t values (1,2)")
<sqlite3.Cursor object at 0x7f9b0e953ad8>
>>> conn.execute("select a / cast(b as real) from t").fetchone()
(0.5,)

关于sqlite - 类型转换问题,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/6085424/

10-12 03:17
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