Different types of MySQL Triggers (with examples)
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 »
Tag Archives: DBMS-SQL
How to implement SQL GROUP BY in Java?
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 »
Common error in Group By
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 »
Categories of SQL Functions
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 »
Query to find 2nd largest value in a column in Table
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 »
MySQL | Group_CONCAT() Function
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 »
MySQL | LEAD() and LAG() Function
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 »
MySQL | PARTITION BY Clause
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 »
Display Sequence of Numbers in SQL Using LEVEL
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 »
Comparisons between DELETE vs DROP in SQL
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 »
Comparisons between SQL vs PLSQL
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 »
Primary key Vs Unique key
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 »
Introduction of NewSQL | Set 2
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 »
Use of NoSQL in Industry
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 »
SQL | Triggers
Trigger is a statement that a system executes automatically when there is any modification to the database. In a trigger, we first specify when the… Read More »
