postgres将文本列值更新为整数列

Question

我有一个包含以下数据的PostgreSQL数据表<​​/ p>

id    assignmentId    folderId    folderId_new
1     2274            5332
2     2274            5348
3     2274            5349
4     2274            5350
46    2277            5355
75    2275            5351
76    2275            5352
77    2275            5353
78    2275            5354
...

和列数据类型

id                serial
assignmentId      integer
folderId          text
folderId_new      integer

我想将folderId列的值保存到folderId_new列 我尝试过以下查询

update framethreshold set folderId_new = CAST (folderId AS integer)

update framethreshold set folderId_new = folderId::int

但会导致错误：

ERROR: invalid input syntax for integer: "" SQL state: 22P02

Answer 1

好的，所以你可以写这个查询

update framethreshold set folderId_new = NULLIF(folderId, '')::int

希望这会奏效;）