ORA 00904 Error: Invalid identifier

Question

I installed Oracle 10g in my virtual XP and created a table using

create table reg1 ( fname varchar2(30), lname varchar2(30), addr varchar2(30), mail varchar2(30), occu varchar2(30), uname varchar2(30), passwd varchar2(30) ); 

and the table is created successfully. But when I try to get the values ​​with a simple query like

 select fname, lname from reg1 where uname="bbb"; 

I get an error like

ORA-00904: "bbb": invalid identifier

I can’t understand what I did wrong here.

Answer 1

Use single quotes.

 select fname,lname from reg1 where uname='bbb'; 

Answer 2

Oracle uses double quotation marks to identify the casing names of objects. For example, the "test" table does not match the test table.

Strings must be enclosed in single quotes, ' .

Fulfilling your request:

 select fname, lname from reg1 where uname = 'bbb'; 

What actually happens in your query, Oracle is trying to find the "bbb" column in the reg1 table, since this column does not exist, you get an error.