Question

下面是我的表结构。

create table "APP".REGISTRATION
(
        "id" INT not null primary key GENERATED ALWAYS AS IDENTITY(START WITH 1,INCREMENT BY 1),
        "firstname" VARCHAR(50),
        "lastname" VARCHAR(50),
        "username" VARCHAR(50),
        "password" VARCHAR(50),
        "email" VARCHAR(50)
);

我插入了一行：

firstname=susheel lastname=singh username=susheel61 password=password email=test@gmail.com

现在我尝试查询

select * from REGISTRATION where USERNAME='susheel61';

我收到错误消息：

> Error code 0, SQL state 42X04: Column 'USERNAME' is either not in any
> table in the FROM list or appears within a join specification and is
> outside the scope of the join specification or appears in a HAVING
> clause and is not in the GROUP BY list. If this is a CREATE or ALTER
> TABLE  statement then 'USERNAME' is not a column in the target table.

Answer 1

抱歉，我无法重现这个。这是ij中的快速会话：

ij> create table "APP".REGISTRATION
> (
>   id INTEGER generated by default as identity (start with 1, increment by 1) not null primary key,
>   firstname VARCHAR(50),
>   lastname VARCHAR(50),
>   username VARCHAR(50),
>   password VARCHAR(50),
>   email VARCHAR(50)
> );
0 rows inserted/updated/deleted
ij> insert into "APP".registration (firstname, lastname, username, password, email) values ('susheel', 'singh', 'susheel61', 'password', 'test@gmail.com');
1 row inserted/updated/deleted
ij> select * from REGISTRATION where USERNAME='susheel61';
ID         |FIRSTNAME                                         |LASTNAME                                          |USERNAME               |PASSWORD                                          |EMAIL
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
1          |susheel                                           |singh                                             |susheel61              |password                                          |test@gmail.com

1 row selected
ij>

请注意，我必须更改您的CREATE TABLE语句才能创建表格。您问题中的CREATE TABLE声明无效;当我尝试运行它时，我收到'语法错误'。

编辑：既然您已经提供了用于创建表格的实际SQL脚本，我可以解释其中的区别。

不同之处在于您已在列名称周围指定了双引号。这样做会使列名称区分大小写。然后，在查询表时必须使用双引号，除非列名都是大写的。如果您没有在名称周围指定双引号，则会将该名称视为全部大写。

以下是如何查询最初指定的表：

ij> create table "APP".REGISTRATION
> (
>   "id" INT not null primary key GENERATED ALWAYS AS IDENTITY(START WITH 1,INCREMENT BY 1),
>   "firstname" VARCHAR(50),
>   "lastname" VARCHAR(50),
>   "username" VARCHAR(50),
>   "password" VARCHAR(50),
>   "email" VARCHAR(50)
> );
0 rows inserted/updated/deleted
ij> select * from "APP".registration where username = 'susheel61';
ERROR 42X04: Column 'USERNAME' is either not in any table in the FROM list or appears within a join specification and is outside the scope of the join specification or appears in a HAVING clause and is not in the GROUP BY list. If this is a CREATE or ALTER TABLE  statement then 'USERNAME' is not a column in the target table.
ij> select * from "APP".registration where "username" = 'susheel61';
id         |firstname                                         |lastname                                          |username                                                  |password                                          |email
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

0 rows selected
ij>

（这次我没有费心插入任何数据，但希望你仍然应该明白：查询完成没有错误。）

请注意，这次列标题是小写的，而上面输出的第一部分中的列标题是大写的。

Answer 2

在我的情况下发生此错误是因为我在WHERE语句中使用双引号而不是单引号

Answer 3

这是我用来创建注册表的脚本，它已成功创建，但在查询具有where条件的表时遇到了问题。

create table "APP".REGISTRATION
(
        "id" INT not null primary key GENERATED ALWAYS AS IDENTITY(START WITH 1,INCREMENT BY 1),
        "firstname" VARCHAR(50),
        "lastname" VARCHAR(50),
        "username" VARCHAR(50),
        "password" VARCHAR(50),
        "email" VARCHAR(50)
);

现在我将其更改为此语法以创建表格，一切正常。不确定原因。

create table "APP".REGISTRATION
(
    id INTEGER generated by default as identity (start with 1, increment by 1) not null primary key,
    firstname VARCHAR(50),
    lastname VARCHAR(50),
    username VARCHAR(50),
    password VARCHAR(50),
    email VARCHAR(50) unique
);

Answer 4

我无法获得该表的create语句，而describe表并没有说明我的问题，但是我必须用双引号将所有表名和列名括起来，并用单引号将值括起来。

SELECT "name" FROM "THING_TABLE" WHERE "name"='Environments';

有趣的是，当我使用ID列时，我不需要引号。邓诺为什么。

可能是创建表的方式。上面说单引号表示表名区分大小写？

德比数据库问题在哪里条件

4 个答案: