The document compares differences between SQL Server and PostgreSQL, cross joins and full outer joins, SQL Server and Oracle, views and stored procedures, and IN and EXISTS clauses. Some key differences include: - PostgreSQL uses COPY instead of BULK INSERT and defaults to a different listening port than SQL Server - A cross join returns all row combinations while a full outer join returns all rows from both tables with NULLs for unmatched fields - SQL Server and Oracle have different default users, data types, and query plan reading directions - Views allow single SELECT queries while stored procedures support multiple statements and parameterization - IN checks for value matches in a subquery while EXISTS only checks if the subquery returns any rows

1. 1.Difference between SQL Server and PostgreSQL
S.No SQL Server PostgreSQL
1 INSERT t VALUES (…) This syntax is not allowed. Allows:
INSERT INTO t VALUES (…)
2 BULK INSERT and BCP uses COPY instead
(which has the functionality of both
BCP and BULK INSERT)
3 Management Studio pgAdmin
4 Bit type Boolean type (accepts values true and
false)
5 IDENITTY Has sequencers (like Oracle)
6 default schema is dbo default schema is PostgreSQL
7 Default Listening on 1433 Default listening on 5432
8 datatype: varchar(max) datatype: text
9 Key is clustered by default key is not clustered by default (and it
is enforced by a constraint and not an
an index!)
10 User Defined Data Types Domains
11 user: sa user: postgres
12 No such thing NATURAL and USING joins
13 SELECT TOP 10 * FROM t SELECT * FROM t LIMIT 10
14 Query plans read from right to left Query plan read from left to right
15 Estimate Query Plan: CTRL+L Estimate Query Plan: F7
2.Difference between Cross Join and Full Outer Join
S.No Cross Join Full Outer Join
1 No join conditions are specified. A combination of both left and right
outer joins.
2 Results in pairs of rows. Results in every row from both of the
tables , at least once.
3 Results in Cartesian product of Assigns NULL for unmatched fields.
two tables.

2. 3.Difference between SQL Server and Oracle
S.No SQL Server Oracle
1 SQL History: Oracle History:
IBM introduced structured Query Oracle Corp is the leading supplier for
Language (SQL) as the language S/w products, headquartered in
to interface with its prototype Redwood shores, California, USA. It
relational database management was founded by Larry Ellison, Bob
system; System R. Oracle Miner and Ed Oates in 1977. Now they
Corporation introduced the first have 43,000 Employees in 150
commercially available SQL countries. Oracle first commercial
relational database management RDBMS was built in 1979, and it is
system in 1979. Today, SQL has the first to support the SQL. Oracle is
become an industry standard, and the first S/w company to develop and
Oracle Corporation clearly leads deploy 100 % Internet-enabled
the world in RDBMS technology. enterprise Software.
SQL is used for all types of DB
activities by all type of users. The
basic SQL commands can be
learned in a few hours and even
the most advanced commands can
be mastered in a few days.
2 SQL (Structure Query Oracle (RDBMS):
Language):
Oracle is fastest and easiest way to
When a user wants to get some create applications in MS windows. It
information from any DB file, he provides the ability to store and access
can issue a query. Structured data. Whether you are experienced or
query language (SQL), new to windows in programming,
pronounced “Sequel”, is the set of Oracle provides you with the complete
commands that all programs and set of tools to simplify rapid
users must use to access data application development. The Oracle
within the Oracle. SQL is a high refers to the method used to create the
performance fault tolerant data graphical user inter face. There is no
base management system. The need to write numerous lines of code
database is mostly maintained by to describe the appearance and location
SQL language, which is conceded of inter face elements.
as the heart of the RDBMS.
3 SQL Technology: Oracle Technology:
SQL is divided into four parts: Oracle DB structure is divided into
two parts, one is called Physical
DDL (Data Definition Language): structure (these files define the
Create, Alter, Drop, Rename, operating system that make up the DB,
Truncate. each Oracle DB is made by three types

3. DML (Data Manipulate of files, data-files, redo logs file-
Language): Select, Update and controls file) and the other is called
Delete, Insert, Into. Logical structure (these files define the
logical areas of storage like schema,
DCL (Data Control Language): table spaces, segments and extents).
Grant, Revoke
TCL (Transaction Control
Language): Commit, Rollback.
4 Advantages: Advantages:
• Provides easy access to all • Data consistency
data. • Integration of data
• Flexibility in data • Easy file generation
molding. • Increased security
• Reduced data storage and • Easy updating of records
redundancy. • No wastage of time
• Provides a high-level • Enforcement of standards
manipulation language. • Controlled data redundancy
• SQL can save data in • Reduce the total expenditures
common PC file formats • Searching of particular data is
that can be imported into easy
other application (like Ms-
• Dispose of heavy files and
Excel).
register work
• SQL is not case sensitive.
• The work of three persons is
• It can enter one or more reduced to one
lines.
• Instant intimation of
• Tabs and indents can be modification of information
used to make code more
readable.
• Can be used by a range of
users.
• It is a nonprocedural
language (English-like
language).
5 Differences: Differences:
• SQL is a tool for all DB • Oracle Corp is the world’s
like DBMS, RDBMS, T- leading supplier of S/w
SQL, and SQL Plus. products.
• SQL maintains different • Oracle is the platform, where
RDBMS. we develop and implement
• SQL is combination of different DB designs and
different commands and software.
functions that why, SQL is • Oracle is the combination of
worked for Oracle DB as a different S/w products, where

4. command prompt they work together for
shell (SQL is the command designing DB.
prompt shell, where we • Oracle works with different
can communicate with any front and back end
DB). products/tools (like SQL).
4.Difference between View and Stored Procedure
S.No View Stored Procedure
1 Does not accepts parameters Accept parameters
2 Can be used as a building block in Cannot be used as a building block in
large query. large query.
3 Can contain only one single Select Can contain several statement like if,
query. else, loop etc.
4 Cannot perform modification to Can perform modification to one or
any table. several tables.
5 Can be used (sometimes) as the Cannot be used as the target for Insert,
target for Insert, update, delete update, delete queries.
queries.
5.Difference between IN and EXISTS
S.No IN EXISTS
1 Returns true if specified value Return true if sub query contain any
matches any value in the sub rows.
query or a list.
2 The sub query will run first and The Outer query will ran first and then
then only outer query. only sub query.
3 IN is slower than EXISTS. The IN Exists is faster than IN.The Outer
is used in the widely For Static query will run first and then only inner
variables for eg: select name from query.So it will reduce the over head.
table where ID in (Select ID from The Exists is useful mostly in IF
table2). conditional statements.
4 Example: Example:
SELECT id, SELECT id,
[Name] [Name]
FROM dbo.tablea FROM dbo.tablea AS a
WHERE id IN (SELECT id WHERE EXISTS (SELECT id2

5. FROM dbo.tableb) FROM dbo.tableb
WHERE id2 = a.id)
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