database Postgres 将列整数更改为布尔值
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Postgres Alter Column Integer to Boolean
提问by samsina
I've a field that is INTEGER NOT NULL DEFAULT 0 and I need to change that to bool.
我有一个 INTEGER NOT NULL DEFAULT 0 字段，我需要将其更改为 bool。
This is what I am using:
这就是我正在使用的：
ALTER TABLE mytabe
ALTER mycolumn TYPE bool
USING
CASE
WHEN 0 THEN FALSE
ELSE TRUE
END;
But I am getting:
但我得到：
ERROR: argument of CASE/WHEN must be type boolean, not type integer
********** Error **********
ERROR: argument of CASE/WHEN must be type boolean, not type integer
SQL state: 42804
Any idea?
任何的想法？
Thanks.
谢谢。
回答by catchdave
Try this:
尝试这个：
ALTER TABLE mytabe ALTER COLUMN mycolumn DROP DEFAULT;
ALTER TABLE mytabe ALTER mycolumn TYPE bool USING CASE WHEN mycolumn=0 THEN FALSE ELSE TRUE END;
ALTER TABLE mytabe ALTER COLUMN mycolumn SET DEFAULT FALSE;
You need to remove the constraint first (as its not a boolean), and secondly your CASEstatement was syntactically wrong.
您需要首先删除约束（因为它不是布尔值），其次您的CASE语句在语法上是错误的。
回答by Rahul Shinde
Postgres can automatically cast integer to boolean. The key phrase is
Postgres 可以自动将整数转换为布尔值。关键语句是
using some_col_name::boolean
-- here some_col_name is the column you want to do type change
Above Answer is correct that helped me Just one modification instead of case I used type casting
以上答案是正确的，对我有帮助 只是一个修改，而不是我使用类型转换的情况
ALTER TABLE mytabe ALTER COLUMN mycolumn DROP DEFAULT;
ALTER TABLE mytabe ALTER mycolumn TYPE bool USING mycolumn::boolean;
ALTER TABLE mytabe ALTER COLUMN mycolumn SET DEFAULT FALSE;
