Start Validating null value in pl sql

Validating null value in pl sql

This will return all rows for which C1 is NULL if the user inputs NULL.

Summary: in this tutorial, you will learn about the PL/SQL record that is a composite data structure, which allows you to manage your data in program more efficiently.

A PL/SQL record is a composite data structure that is a group of related data stored in SET SERVEROUTPUT ON SIZE 1000000; DECLARE r_emp employees%ROWTYPE; n_emp_id employees.employee_id%TYPE := 200; BEGIN SELECT * INTO r_emp FROM employees WHERE employee_id = n_emp_id; -- print out the employee's first name DBMS_OUTPUT.

The following illustrates the syntax of the defining programmer-defined record with SET SERVEROUTPUT ON SIZE 1000000; DECLARE TYPE t_name IS RECORD( first_name employees.first_name%TYPE, last_name employees.last_name%TYPE ); r_name t_name; -- name record n_emp_id employees.employee_id%TYPE := 200; BEGIN SELECT first_name, last_name INTO r_name FROM employees WHERE employee_id = n_emp_id; -- print out the employee's name DBMS_OUTPUT.

PUT_LINE(r_name.first_name || ',' || r_name.last_name ); END; / SET serveroutput ON SIZE 1000000; DECLARE TYPE t_name IS RECORD( first_name employees.first_name%TYPE, last_name employees.last_name%TYPE ); r_name t_name; r_name2 t_name; r_name_null t_name; n_emp_id employees.employee_id%TYPE := 200; BEGIN -- assign employee's infomation to record SELECT first_name, last_name INTO r_name FROM employees WHERE employee_id = n_emp_id; -- assign record to another record r_name2 := r_name; -- print out the employee's name DBMS_OUTPUT.

A user gives an input and then i have to display all records that match this value in C1, if user inputs null then all nullls should be displayed How can I do this in sql. You should be able to do something like: select * from t1 where decode('&user_input',null,1,0) = 1 and c1 is null union all select * from t1 where decode('&user_input',null,0,1) = 1 and c1 = '&user_input' It's not pretty, and Tom's right, your data model should represent that which can be represented by the database, but the above might work if you're stuck and have no alternatives. As per Tom's example last line *null* *null* *null* Null is never equal to or not equal to NULL.

if I do SELECT * FROM T1 WHERE C1 = &USER_INPUT if user inputs NULL then this query will return no records is there any way to consider NULL = NULL for this query? Its result is unknown So why does NULLIF returns null ?

Hi, I have a table with one column DESC t1 C1 VARCHAR2(200) Now this column contains alphanumeric values as well as some nulls.

In my application we consider NULL is equal to NULL. If they are not equal, then the function returns expr1. Regarding this query: SELECT * FROM T1 WHERE C1 = &USER_INPUT Where the user may supply a NULL.

I thought we can only compare nulls to nulls in decodes or NVL or NVL2.

CREATE TABLE T1 (C1 VARCHAR2(4)); SELECT * FROM T1 WHERE NVL(C1,'XXXXX') = NVL(&USER_INPUT, 'XXXXX') I replace NULL with five 'X' characters which is greater than the maximum length of C1 i.e VARCHAR2(4).

Define CHECK constraint at column level with other column attributes, CREATE TABLE student_info( no NUMBER(3) PRIMARY KEY, stu_code VARCHAR(10) CHECK (stu_code like 'j%'), name VARCHAR(30) CHECK ( name = upper(name) ), city VARCHAR(30) CHECK (city IN ('Houston','San Antonio','Boston','Miami')) scholarship NUMBER(5) CHECK (scholarship BETWEEN 500) ); Table created.