如何将布尔数据类型列添加到 sql 中的现有表？
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How to add a boolean datatype column to an existing table in sql?
提问by Mike
I have a table called personin my database. I want to add another column to the same table and it's a Boolean datatype column. I have tried following queries but it says syntax errornear default. I know this is a common and there are lot of answers. I have tried many of them and couldn't figure out to make it work. So please help me.
我的数据库中有一个名为person的表。我想在同一个表中添加另一列，它是一个 Boolean 数据类型 column。我试过下面的查询，但它说接近默认的语法错误。我知道这是一个常见问题，并且有很多答案。我已经尝试了很多，但无法弄清楚如何让它工作。所以请帮助我。
queries I have tried
我试过的查询
ALTER TABLE person add column "AdminApproved" BOOLEAN SET default FALSE;
ALTER TABLE person alter column "AdminApproved" BOOLEAN SET default FALSE;
I have tried without SETkey word too.
我也试过没有SET关键字。
回答by P?????
In SQL SERVER it is BIT, though it allows NULLto be stored
在 SQL SERVER 中它是BIT，虽然它允许NULL存储
ALTER TABLE person add [AdminApproved] BIT default 'FALSE';
Also there are other mistakes in your query
您的查询中还有其他错误
When you alter a table to add column no need to mention
columnkeyword inalterstatementFor adding default constraint no need to use
SETkeywordDefault value for a
BITcolumn can be('TRUE' or '1')/('FALSE' or 0).TRUEorFALSEneeds to mentioned asstringnot as Identifier
当您更改表以添加列时，无需
column在alter语句中提及关键字添加默认约束无需使用
SET关键字BIT列的默认值可以是('TRUE' or '1')/('FALSE' or 0)。TRUE或FALSE需要提及string不作为标识符
回答by MEC
The answer given by P?????creates a nullable bool, not a bool, which may be fine for you. For example in C# it would create: bool? AdminApprovednot bool AdminApproved.
P给出的答案？？？？创建一个可为空的 bool，而不是 bool，这对您来说可能没问题。例如在 C# 中它会创建：bool? AdminApprovednot bool AdminApproved.
If you need to create a bool (defaulting to false):
如果您需要创建一个 bool（默认为 false）：
ALTER TABLE person
ADD AdminApproved BIT
DEFAULT 0 NOT NULL;
回答by Zafar Faheem
In phpmyadmin, If you need to add a boolean datatype column to an existing table with default value true:
在 phpmyadmin 中，如果您需要将布尔数据类型列添加到默认值为 true 的现有表中：
ALTER TABLE books
isAvailable boolean default true;
