Answer Posted / tanu

UNION: Union Combines results of all select statements,
displaying duplicate rows only one time in the answerset.

Rules for usage:
1. All select clauses must have same number of expressions.
2. Corresponding expressions must have compatible domains.

First SELECT statement:
->Determines output format.
->Determines output title.

Last SELECT statement:
->Contains ORDER BY for the entire result, if required.

EXAMPLE:
SELECT first_name
,last_name
,'employee' (TITLE 'employee//type')
FROM employee
WHERE manager_employee_number = 1019
UNION
SELECT first_name
,last_name
,' manager '
FROM employee
WHERE employee_number = 1019
ORDER BY 2
;

RESULT:

first_name last_name employee_type
Carol Kanieski employee
Ron Kubic manager
John Stein employee

JOIN:
Join is a technique for accessing data from more than one
table in a single answerset. Each row in the answerset may
contain data from columns of more than one table. Tables
are joined on columns sharing common domain.

Is grant a ddl statement?

901

---

what is the difference between clustered and non clustered index in sql? : Sql dba

1129

---

What are different clauses used in sql?

1117

---

What is the difference between in and between in sql?

1065

---

Explain the difference in execution of triggers and stored procedures?

1022

---

What does varchar include?

953

---

What is sqlite format?

1202

---

How can you fetch common records from two tables?

1063

---

What is scope of pl sql developer in future?

1022

---

Can we alter stored procedure?

991

---

What are commit, rollback, and savepoint?

999

---

Which function is used to return remainder in a division operator in sql?

1143

---

define sql insert statement ? : Sql dba

1032

---

What is the command used to fetch first 5 characters of the string?

1403

---

List the various privileges that a user can grant to another user?

1043

---