Technical Interview Questions and Answers :: Societe Generale
- Select All
- Oracle PLSQL
- SQL
- Java
- C++
- Informatica
- WebMethod
- DBMS
- C
- Soft. Engineering
- Data Structure
- HR Question in TR
11 / 75
No Discussion on this question yet!
12 / 75
A query with respect to DBMS relates to user commands that are used to interact with a database. The query language can be classified into data definition language and data manipulation language.
13 / 75
Subqueries, or nested queries, are used to bring back a set of rows to be used by the parent query. Depending on how the subquery is written, it can be executed once for the parent query or it can be executed once for each row returned by the parent query. If the subquery is executed for each row of the parent, this is called a correlated subquery.
A correlated subquery can be easily identified if it contains any references to the parent subquery columns in its WHERE clause. Columns from the subquery cannot be referenced anywhere else in the parent query. The following example demonstrates a non-correlated subquery.
E.g. Select * From CUST Where '10/03/1990' IN (Select ODATE From ORDER Where CUST.CNUM = ORDER.CNUM)
14 / 75
No Discussion on this question yet!
15 / 75
No Discussion on this question yet!
16 / 75
No Discussion on this question yet!
17 / 75
No Discussion on this question yet!
18 / 75
No Discussion on this question yet!
19 / 75
No Discussion on this question yet!
20 / 75
USED TO CONVERT HIERACHICAL STRUCTURE TO THE FLAT STRUCTURE. IT IS USED TO JOIN A TABLE ITSELF AS LIKE IF THAT IS THE SECOND TABLE