Showing posts with the label oracle

get Fifth highest paid employee details in sql | limit | offset

Get Fifth highest paid employee details in sql SELECT * FROM employee ORDER BY salary ASC LIMIT 1 OFFSET 5.  ORDER BY salary ASC - by this we are arranging salary in Ascending order. LIMIT 1 - By this we are fetching only one employee details. OFFSET 5 - By this we are start fetching record from 5th number record.

DATATYPES in sql || Sql Tutorial -5

DATATYPES IN SQL  The data type represents the type of data to be entered into a column and Db engine can assign memory for thevalue entered into the column. There are 5 types of DataType in sql. String DataTypes Numeric DataTypes Date Datatypes Binary DataTypes LOB--Large Objects String Data Types These data types support sequence of character, digits and any symbol from keyboard. CHAR(size) It is used to store fixed length character strings. By default the size is 1 character, and max size is 2000 chars orbytes. Ex: student_id, email, address and so on VARCHAR2(size) It is used to store variable length character strings. No default size. we should specify size and max size is 4000 chars /bytes. Ex: emp names, addresses, descriptions, city names. LONG It is used to store variable length char data(similar to varchar2 data type) but max size is 2 GB NOTE: Only one long type column is allowed per a table. 1) NUMBER(Precision, [Scale])    It is used to store numb

Naming convention in SQL Sql Tutorial -4

Naming Convention in SQL Rules to follow before specifying names(Object names, Column Names and Variable Names). Each name should begins alphabet Valid character set is a-z,A-Z,0-9,@,$,# and _ (underscore) Ex:  Emp123   Emp_o11 Names are not case sensitive Already existed names are not allowed Pre defined keywords (ReservedWords) are not allowed as names. Blankspace within a name is not allowed Max length of any name is 32 chars

SQL COMMANDS || Oracle SQL COMMANDS Sql Tutorial -3

Types of SQL commands 1) DDL(data definition language) commands:       Used to create or change or delete any data base objects CREATE ALTER DROP TRUNCATE RENAME 2) DML(data manipulation language) COMMANDS       Used to fetch data / enter new data/ changing existed data / deleting the data from table. INSERT  UPDATE  DELETE  TRUNCATE 3) DRL(dataretrieval language) Command     SELECT (logicalcommand) 4) DCL(DATA CONTROL LANGUAGE) COMMANDS     Used to control the access of data base objects. These commands are used by DBA (databaseadministrator) GRANT  REVOKE 5) TCL(TRANSACTION CONTROL LANGUAGE) COMMANDS      Used to save or cancel the actions/transactions made on table data. COMMIT  ROLLBACK  SAVEPOINT

Features of Sql * Plus

Features of Sql * Plus At a time only one query is allowed to execute Sql queries are not case sensitive Each query is terminated with ; ( semi colon ) SQL commands are ANSI standard ( American National standard institute )

What is sql definition(Structured query language). Sql Tutorial -2

Structured query language It is a collection of pre defined commands and constructs with syntactical rules. 1. Sql is a client tool to interact with ORACLE DB /any DB 2. Sql is to be installed in to the system whenever we have installed the db software. 3. Client [Technical] requests should be submitted in the form of "Queries". 4. Queries are executed by SQL STMT EXECUTOR ( Oracle Db Engine ) 5. Queries are executed against database and output will be displayed on the Sql * plus window.

What is sql in Deep(Structured query language). Sql Tutorial -1

What is sql in Deep(Structured query language) Oracle was the first company to release a product that used the English-based Structured Query Language, or SQL. This language allows end users to extract information themselves, without using a systems group for every little report. Oracle’s query language has structure, just as English or any other language has structure. It has rules of grammar and syntax, but they are basically the normal rules of careful English speech and can be readily understood. What is SQL QUERIES It is known as data base language. It is used to communicate with any database. We can use this language constructs to write SQL QUERIES. What is SQL* PLUS SQL * PLUS is a default client tool and acts as an interface between client and database. What is SQL It is a collection of pre defined commands and constructs with syntactical rules