I want to generate an output with blank/empty column with a "Select" query in oracle. I'm able to achieve this with below sql query:
SELECT CustomerName AS Customer, "" AS Contact
FROM Customers;
So when I run above sql query it returns a table with two columns "Customer" column with content in it and "Contact" column with no content or blank column.
I want to achieve same with oracle query. Any help will be highly appreciated.
I think you should use null
SELECT CustomerName AS Customer, null AS Contact
FROM Customers;
And Remember that Oracle
treats a character value with a length of zero as null.
In DB2, using single quotes instead of your double quotes will work. So that could translate the same in Oracle..
SELECT CustomerName AS Customer, '' AS Contact
FROM Customers;
I guess you will get ORA-01741: illegal zero-length identifier if you use the following
SELECT "" AS Contact FROM Customers;
And if you use the following 2 statements, you will be getting the same null value populated in the column.
SELECT '' AS Contact FROM Customers; OR SELECT null AS Contact FROM Customers;
Related
I am new to oracle and I would like to know how do we check the nulls in non null columns in oracle tables as part of the ETL testing process. (The two tables could be T1 and T2). Please let me know a sample query.
I have already tried
select count(*) from T2 where T2.column is Null;
Thanks, Santosh
'=' operator can not be used while comparing to null. Replace '=' to 'is' as per below query.
select count(*) from T2 where T2.column is Null;
Assume there is column name: id in the table record, and id should not contain any null value. Query to check this is:
select id from record where id is null;
I tried with following queries, these queries giving only the count of null values, What i need was to do a null check and return the column name.
select count(*)-count(columnA), count(*)-count(columnB) from table;
select count(*) from table where columnA is null;
You can also do
SELECT
SUM(IF(columnA is NULL,1,0)) as canulls,
SUM(IF(columnB is NULL,1,0)) as cbnulls
FROM table;
This will also give you the number of null fields for each columns.
I am using Oracle Database.
I have view called VW_MREQ
It has column as follows :
M_Product_ID
AD_Client_ID
AD_ORG_ID
It has records inside.
Then, I have empty table called M_Requisition
It has column as follows :
M_Product_ID
AD_Client_ID
AD_ORG_ID
DESCRIPTION
CREATEDBY
I am making Procedure and would like to insert Data manually to M_Requisition, the foreign key is M_Product_ID and I want the AD_Client_ID and AD_ORG_ID to be the same as in VM_REQ as I insert M_Product_ID to M_Requisition manually.
INSERT INTO M_Requisition(M_Product_ID, AD_Client_ID, AD_ORG_ID, DESCRIPTION, CREATEDBY) VALUES(123, ?? , ??,"Insert Data","Me")
I plan to use SELECT INTO but still confused how I arrange it as I am newbie in Oracle.
Your help will be useful.
You could use the insert-select syntax, and just query the hardcoded values as literals:
INSERT INTO M_Requisition
(M_Product_ID, AD_Client_ID, AD_ORG_ID, DESCRIPTION, CREATEDBY)
(SELECT 123, AD_Client_ID, AD_ORG_ID, 'Insert Data', 'Me'
FROM VW_MREQ)
everybody. I have table, where one of the column names is "All" and I want to get this column. I trying to use next simple query:
SELECT All
FROM TableName
, but I have ORA-00936. When I use just:
SELECT *
FROM TableName
I see required column with "All" name. In table specification I see next SQL script:
create table TableName
(
houseid NUMBER not null,
id NUMBER not null,
note VARCHAR2(255),
all NUMBER
)
How I can get access to "All" column?
SELECT "ALL" from TABLENAME
this is a good reason not to use oracle reserved keywords as table or column names but by using the doublequote " " you can access them.
Keep in mind that when you use " " you must be consistent in your case in the statement. Not "All" and "all" in the same statement
Put it in quotes.
SELECT "all"
FROM TableName
This is my query,
CREATE VIEW employee_vu AS(
SELECT employee_id,last_name "employee",department_id
FROM employees);
I am giving alias of columns in lower case ,and in it is stored in lower case
after doing desc i have confirmed.
But when i am trying to select this column employee :error occurs
EMPLOYEE: invalid identifier
Since all column name is stored in upper case ,is this the problem,Please explain what is the concept behind!
You would need to select it using double quotes and matching case:
select employee_id, "employee", department_id from employees;
That's why creating columns with double quoted identifiers is considered bad practice in Oracle.