SQL INTERVIEW QUESTION & ANSWERS
| 141. |
What is the difference between UNION and UNION ALL SQL syntax? |
| |
UNION SQL syntax is used to select information from two tables. But it selects only distinct records from both the table, while UNION ALL selects all records from both the tables. |
| 142. |
What are the different types of parameter modes? |
| |
Parameter modes define the behavior of formal parameters of subprograms.There are three types of parameter modes :- IN
- OUT
- IN / OUT
|
| 143. |
What type of cursor allows you to use all the fetch orientation options in a FETCH statement? |
| |
Scrollable cursor |
| 144. |
Define Joins? |
| |
- A join combines columns and data from two or more tables.
- The tables are listed in the from clause of the select statement.
- With joins, the information from any number of tables can be related.
- The condition of the query can refer to any columns of any table joined.
|
| 145. |
What are the diffeerent types of joins? |
| |
There are four types of joins are :- Equi Join
- Self Join
- Cartesian join
- Outer join :Full , Left , Right
|
