Souy Soeng

Understanding SQL Primary Key In SQL, a Primary Key is a constraint that uniquely identifies each record in a table. It ensures that no two rows in …

SQL CHECK Constraint The CHECK constraint in SQL is used to enforce specific rules for the values that a column can hold. It ensures that all rows i…

SQL NOT NULL Constraint The NOT NULL constraint in SQL ensures that a column cannot have a NULL value. It enforces that every row must have a value…

SQL UNIQUE Constraint The UNIQUE constraint in SQL ensures that all the values in a specified column or a combination of columns are distinct. It pr…

SQL FOREIGN KEY Constraint A FOREIGN KEY is a column (or a set of columns) in one table that refers to the PRIMARY KEY in another table. It creates…

Understanding SQL ALTER TABLE The SQL ALTER TABLE statement is used to modify the structure of an existing table. It allows you to add, delete, or c…

SQL DROP TABLE The DROP TABLE statement in SQL is used to delete an entire table from the database. This operation removes both the table structure …

SQL TRUNCATE TABLE The TRUNCATE TABLE statement in SQL is used to quickly delete all rows from a table without removing its structure or associate…

Understanding SQL CREATE TABLE The SQL CREATE TABLE statement is used to create a new table in a database. A table consists of columns and rows, whe…

Understanding SQL INSERT The SQL INSERT statement is used to add new rows of data into a table. It is one of the fundamental Data Manipulation Lan…

Understanding SQL UPDATE The SQL UPDATE statement is used to modify existing records in a table. It allows you to update one or more rows based on s…

Understanding SQL DELETE The SQL DELETE statement is used to remove rows from a table. It allows you to delete specific rows based on conditions or …

Understanding the SQL ANY Operator The SQL ANY operator is used in conjunction with comparison operators (like = , < , > , <= , >= , an…

Understanding SQL ALL The SQL the  ALL operator is used with comparison operators ( = , != , < , > , <= , >= ) to compare a value agains…

Understanding the SQL EXISTS Operator The SQL EXISTS operator is used to check the existence of records returned by a subquery. It returns TRUE if…

Understanding SQL MINUS The SQL MINUS operator is used to compare two SELECT queries and return the rows that are present in the first query but no…

Understanding SQL Subqueries A subquery, also known as an inner query or nested query, is a query within another SQL query. The subquery provides dat…

SQL Correlated Subquery A correlated subquery in SQL is a subquery that refers to columns from the outer query. It is evaluated once for every row p…

SQL CUBE The CUBE operator in SQL is an extension of the GROUP BY clause. It allows you to generate subtotals for all combinations of columns speci…

SQL UNION The UNION operator in SQL combines the result sets of two or more SELECT queries into a single result set. It removes duplicate rows by d…