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: F72.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.
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
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
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
FROM dbo.tableb) FROM dbo.tableb WHERE id2 = a.id)Please visit my blog @ http://onlydifferencefaqs.blogspot.in/