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SQL Constraints

What are the SQL Constraints? SQL constraints are rules that limit the types of data that can be inserted or updated into a table. Constraints are used to enforce data integrity and ensure the accuracy and consistency of data. Constraints could be either on a column level or a table level. The column-level constraints are […]

March 31, 2023 | DBMS | No comments

SQL: AND & OR operators

The AND and OR operators are used in SQL to filter data and produce precise results based on conditions. Multiple conditions can also be combined using the SQL AND & OR operators. In a SELECT, INSERT, UPDATE, or DELETE statement, these two operators can be combined to test for multiple conditions. Note: It is critical […]

March 31, 2023 | DBMS | No comments

SQL: DISTINCT keyword

What is the SQL DISTINCT keyword? The SQL DISTINCT keyword is used in conjunction with the SELECT statement to remove all duplicate records and only return unique records. DISTINCT can also be used in conjunction with aggregate SQL functions such as COUNT, MAX, SUM, AVG, and so on. DISTINCT operates not only on a single […]

March 29, 2023 | DBMS | No comments

SQL: HAVING Clause

The HAVING clause in SQL Server includes one or more conditions that must be TRUE for groups of records. It’s similar to the GROUP BY clause’s WHERE clause. The only distinction is that the WHERE clause cannot be used with aggregate functions, whereas the HAVING clause can. The HAVING clause is always followed by the […]

March 28, 2023 | DBMS | No comments

SQL: Group By Clause

The SQL Group By statement is used to organize similar data into groups. The data is further organized using an equivalent function. It means that if multiple rows in a specific column have the same values, they will be grouped. The SELECT statement is combined with the GROUP BY clause in a SQL query: The […]

March 28, 2023 | DBMS | No comments

SQL: ORDER BY Clause

What is the ORDER BY Clause? In the SELECT query, the ORDER BY clause can be used to sort the result in ascending or descending order of one or more columns. ORDER BY by default sorts the data in ascending order. We can sort the data in descending order with the keyword DESC and ascending […]

March 26, 2023 | DBMS | No comments

SQL: LIKE clause

In SQL to filter data based on a specific pattern, the LIKE clause is used in the WHERE condition. It can be applied to date, string, or numeric values. However, using the string values is advised. Uses of LIKE clause in SQL: The following are some examples of how the LIKE clause is used: Enables […]

March 25, 2023 | DBMS | No comments

SQL: WHERE clause

When retrieving data from a single table or by joining data from multiple tables, a condition is specified using the SQL WHERE clause. If the given condition is satisfied, then only it returns a specific value from the table. The WHERE clause should be used to filter the records and only retrieve those that are […]

March 24, 2023 | DBMS | No comments

SQL: DELETE Query

What is Delete Query? In SQL, the DELETE Query removes existing records from a table. Depending on the condition specified in the WHERE clause, we can delete a single record or multiple records. NOTE: This command must be used with extreme caution because it permanently deletes the data. Syntax: where table_name is the table that has […]

March 22, 2023 | DBMS | No comments

SQL: UPDATE Query

What is an UPDATE QUERY? The SQL UPDATE statement is used to modify the data in tables’ records. A condition determines which rows are to be updated. The WHERE clause is used to specify conditions. Syntax: where, table_name: name of the table column_name: name of first, second, third column… expression: new value for first, second, […]

March 17, 2023 | DBMS | No comments

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