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Data is filtered in SQL using WHERE clauses and HAVING clauses. HAVING clauses are a little more challenging where clauses are easy to understand. The data in the table is filtered using WHERE clauses. They are contrarily filtering the data using clauses after grouping and aggregation. Another way to say it is that instead of working on grouped records, one would focus on individual records.
Although almost 50% of developers assert that the WHERE clause is used in all SELECT queries and the HAVING clause is only used in SELECT queries that include the total capacity or gathering by Clause, this is incorrect. Enrol in our MYSQL certifications to sharpen your MySQL skills and restore confidence.
Where Clause vs HAVING Clause
Data is gathered using the structured query language, or SQL from databases and is comprehensive or declarative. How the Where and Having clauses vary in SQL is one of the most often asked topics by novices in SQL and database interview questions. Since programming languages typically require more than one ability, assessing a candidate’s database expertise during Java or.Net interviews is normal practice. Many Java programmers and.NET developers, who aren’t meant to know SQL, cannot respond to this question. However, the majority of programmers believe that clauses are used in all SELECT queries.
WHERE Clause
We may use a conditional phrase known as the WHERE Clause to filter the results. We may set a selection criterion using this WHERE Clause to choose the needed records from a table. The WHERE clause functions similarly to an if condition in every programming language. This Clause compares the provided value to a MySQL table’s field value. The row is returned if the value provided from outside is equivalent to the available field value in the MySQL table.
When merging several tables, the WHERE Clause filters the records from the table. Only the records that meet the criteria stated in the WHERE clause will be retrieved. It may be used with statements that SELECT, UPDATE, or DELETE data.
HAVING Clause:
SQL’s HAVING Clause and GROUP BY Clause can be used. HAVING Clause makes obtaining the values of groups that meet specific requirements easier. In most cases, the Where clause is utilised along with the Having Clause. The where Clause filters each row, whereas the having clause filters aggregated or summarised data. To filter groups based on certain criteria, the HAVING clause is frequently used in conjunction with the GROUP BY Clause. The HAVING clause works like the WHERE clause if the GROUP BY Clause is absent.
Main Differences Between WHERE and HAVING Clause
| Where Clause | Having Clause |
| It filters the table’s records according to a certain criterion. | It excludes records from the groups according to a certain criterion. |
| You can use it without using the “GROUP BY” phrase | Without the ‘GROUP BY’ phrase, it cannot be used. |
| Row operations can be utilised with it. | With the column operation, it functions. |
| The aggregate functions cannot be contained in it. | The aggregate functions may be present. |
| It is compatible with the statements “SELECT,” “UPDATE,” and “DELETE.” | It is only appropriate for usage with the SELECT query. |
| If necessary, it comes before the “GROUP BY” phrase. | It is employed following the “GROUP BY” phrase. |
| It combines single-row functions like “UPPER” and “LOWER.” | It is compatible with several row functions, including “SUM” and “COUNT.” |
| The WHERE clause is initially applied to individual rows or table-valued items in the Diagram pane. Only the rows that comply to the restrictions in the WHERE clause are grouped. | The results set rows are then given the HAVING clause to apply. The query result only contains the groups that satisfy the HAVING requirements. |
