PostgreSQL sql command error column 'does not exist'

Question

dxdb=> \d dxtest_loadprofiletosale
                            Table "public.dxtest_loadprofiletosale"
   Column    |   Type   |                               Modifiers                               
-------------+----------+-----------------------------------------------------------------------
 id          | integer  | not null default nextval('dxtest_loadprofiletosale_id_seq'::regclass)
 TransDate   | date     | 
 IssueDate   | date     | 
 CustomerNum | smallint | not null
Indexes:
    "dxtest_loadprofiletosale_pkey" PRIMARY KEY, btree (id)

dxdb=> INSERT INTO dxtest_loadprofiletosale(id, TransDate, IssueDate, CustomerNum) VALUES(1, '2015-03-04','2015-01-01',01);
ERROR:  column "transdate" of relation "dxtest_loadprofiletosale" does not exist
LINE 1: INSERT INTO dxtest_loadprofiletosale(id, TransDate, IssueDat...

excuse me,I already has the column "transdate", why it said does not exist?

Answer 1

Your column is called "TransDate" not transdate. You created your table using double quotes for the column names, which makes them case sensitive and you must use double quotes all the time:

INSERT INTO dxtest_loadprofiletosale
  (id, "TransDate", "IssueDate", "CustomerNum") 
VALUES
  (1, '2015-03-04','2015-01-01',01);

More details about SQL identifiers are in the manual:
http://www.postgresql.org/docs/current/static/sql-syntax-lexical.html#SQL-SYNTAX-IDENTIFIERS

In general it is better to never use double quotes - it will give you a lot less trouble in the long run.