Difference between DDL and DML in DBMS
Prerequisite – DDL, DQL, DML, DCL and TCL Commands DDL: DDL is Data Definition Language which is used to define data structures. For example: create… Read More »
Prerequisite – DDL, DQL, DML, DCL and TCL Commands DDL: DDL is Data Definition Language which is used to define data structures. For example: create… Read More »
A MySQL trigger is a stored program (with queries) which is executed automatically to respond to a specific event such as insertion, updation or deletion… Read More »
Prerequisites: Java Collections, Java Array List, Comparator Interface in Java Given a list object containing multiple records, our task is to perform SQL group by… Read More »
Prerequisite: SQL | GROUP BY Error: Column ‘col’ is invalid in the select list because it is not contained in either an aggregate function or… Read More »
SQL Functions are developed into Oracle Database and are available to use in various appropriate SQL Statements. Functions in SQL and User defined function in… Read More »
Problem: Write a SQL query to find the 2nd largest value in a column in a table. Examples: In the 1st example find the 2nd… Read More »
The GROUP_CONCAT() function in MySQL is used to concatenate data from multiple rows into one field. This is an aggregate (GROUP BY) function which returns… Read More »
The LEAD() and LAG() function in MySQL are used to get preceding and succeeding value of any row within its partition. These functions are termed… Read More »
A PARTITION BY clause is used to partition rows of table into groups. It is useful when we have to perform a calculation on individual… Read More »
The term LEVEL refers to a Pseudocolumn in Oracle which is used in a hierarchical query to identify the hierarchy level (parent->child) in numeric format.… Read More »
Prerequisite – SQL Commands DELETE is a Data Manipulation Language (DML) command and used when you want to remove some or all the tuples from… Read More »
Introduction SQL: Structured Query Language (SQL) is a standard Database language which is used to create, maintain and retrieve the relational database. The advantages of… Read More »
Prerequisite – Keys in Relational Model A primary key is a column of table which uniquely identifies each tuple (row) in that table. Primary key… Read More »
Prerequisite – Introduction to NoSQL, Difference between SQL and NoSQL The term NewSQL is not exactly as wide as NoSQL. NewSQL systems all begin with… Read More »
Prerequisite – Introduction to NoSQL, Difference between SQL and NoSQL Why NoSQL? In recent times you can easily capture and access data from various sources,… Read More »