Question

我想将VARCHAR转换为INT，但在我的表中我有一些像'???'的值然后SQL Server启动此expcetion：

Conversion failed when converting the varchar value '????' to data type int.
Severity 16

我可以转换这个'???'为NULL，这没问题，但是怎么做？

我正在尝试做这样的事情：

INSERT INTO labbd11..movie(title, year)
SELECT movies.title, 
       CASE movies.mvyear IS '????' THEN NULL ELSE CAST (movies.mvyear AS INT)
FROM disciplinabd..movies

但没有任何作用..

任何想法的人？

Answer 1

您可能只想解决这个问题并以相同的方式处理任何非int值

 INSERT INTO labbd11..movie(title, year) 
    SELECT movies.title, 
           CASE WHEN IsNumeric(movies.mvyear+ '.0e0') <> 1  THEN NULL 
                ELSE CAST (movies.mvyear AS INT) END  
      FROM disciplinabd..movies

请参阅此question

Answer 2

我相信你会想要像

这样的东西

INSERT INTO labbd11..movie(title, year) 
  SELECT movies.title, 
         CAST( CASE movies.mvyear 
                    WHEN '????' THEN NULL 
                    ELSE movies.mvyear
                 END AS INT) 
    FROM disciplinabd..movies

您希望CASE语句返回VARCHAR（MVYEAR或NULL），然后您希望CAST对CASE的结果进行操作。

Answer 3

    INSERT INTO labbd11..movie(title, year) 
    SELECT movies.title, 
           CASE WHEN movies.mvyear = '????' THEN NULL 
                ELSE CAST (movies.mvyear AS INT) END  
      FROM disciplinabd..movies

Answer 4

INSERT INTO labbd11..movie(title, year)
    SELECT
        movies.title,
        CAST(CASE WHEN movies.mvyear = '????' THEN NULL ELSE movies.mvyear END AS INT)
    FROM
        disciplinabd..movies

Answer 5

您也可以使用：

CAST(NULLIF(movies.mvyear,'????') AS INT)

SQL：如何在查询中使用用例和强制转换？

5 个答案: