sql subquery
Posted inOracle PL/SQL MY SQL SQL

SQL Subquery

Summary: In this tutorial, you’ll learn how to use SQL subqueries to form flexible queries for retrieving data from the database. Introduction to SQL subquery  A subquery is an SQL query nested inside another query. The query that contains a subquery is known as an outer query. To write a subquery,…
left join in sql
Posted inMY SQL Oracle PL/SQL SQL

SQL LEFT JOIN

Summary: in this tutorial, you’ll learn how to use the SQL LEFT JOIN clause to merge rows from two tables. Introduction to SQL LEFT JOIN clause  The LEFT JOIN clause is an optional clause of the SELECT statement. The LEFT JOIN clause allows you to merge rows from two tables. Here’s the syntax of LEFT JOIN clause: SELECT column1, column2…
sql inner join
Posted inSQL

SQL INNER JOIN

Summary: In this tutorial, you will learn how to use the SQL INNER JOIN clause to merge rows from two tables based on a condition. Introduction to the SQL INNER JOIN clause  The INNER JOIN is an optional clause of the SELECT statement. The INNER JOIN clause allows you to merge rows from two related tables. Here’s the…
Posted inSQL Oracle PL/SQL SQL Server

SQL Server autoincrement

Autoincrement, also known as an identity column or auto-incrementing field, is a feature in SQL Server and many other relational database management systems (RDBMS) that simplifies the process of generating unique, sequential values for a column in a table. This feature is commonly used for primary keys, ensuring that each…
Posted inSQL SQL Server

Select rows with max value

In SQL, you can use the SELECT statement with the MAX() function to retrieve rows that have the maximum value in a specific column or set of columns. This is a common operation when you want to find the records with the highest or maximum values in a dataset. Let’s dive into how to…
Posted inSQL SQL Server

SQL TOP

The SQL TOP clause used to limit the number of rows returned by a query. It is often used when you want to retrieve a specific number of rows from a table that meet certain criteria, or when you want to retrieve the first N rows of a result set. SQL TOP…
Posted inMY SQL SQL

SQL HAVING COUNT

In SQL, the HAVING clause is used in combination with the COUNT function to filter the results of a query based on the count of rows returned by a particular condition. This clause is typically used in conjunction with the GROUP BY clause to aggregate data and then filter the aggregated results. Here’s an…
Posted inMY SQL Oracle PL/SQL SQL

SQL remove duplicates

Removing duplicates from a SQL database is a common task that can help improve data quality and query performance. Duplicates occur when there are multiple rows in a table with identical values in one or more columns. You can eliminate these duplicates using various SQL techniques and clauses. In this…
Posted inSQL MY SQL Oracle PL/SQL

SQL MERGE

The SQL MERGE statement stands out as a versatile tool for consolidating data from multiple sources and maintaining data integrity. It serves as a powerful alternative to the more traditional approach of using individual INSERT, UPDATE, and DELETE statements to manage data changes. The MERGE statement’s ability to handle these operations within a single statement offers…
Posted inMY SQL Oracle PL/SQL SQL

SQL TCL statements

Transaction Control Language (TCL) in SQL is a subset of SQL commands used to manage database transactions. Transactions are a fundamental concept in database systems, ensuring data integrity and consistency by grouping a set of SQL statements into a single logical unit of work. TCL commands allow developers to control when changes…