ORACLE SQL CAST IN CASE 语句

Question

有没有办法在 CASE 语句中将 CAST 转换为 INTEGER ？

CASE 
WHEN SV.END_DATE IS NOT NULL THEN SV.END_DATE - SV.START_DATE 
ELSE 0
END AS DAYDIFF

Answer 1

是的，您可以将该值转换为不带小数部分的数字数据类型：

CASE 
  WHEN SV.END_DATE IS NOT NULL THEN
    CAST(SV.END_DATE - SV.START_DATE AS NUMBER(38))
  ELSE 0
END AS DAYDIFF

或者您可以截断 result，这也会删除值的小数部分：

CASE 
  WHEN SV.END_DATE IS NOT NULL THEN
    TRUNC(SV.END_DATE - SV.START_DATE)
  ELSE 0
END AS DAYDIFF