What is INDEXING in SQL? 📢   ✔️ Indexes are special lookup tables that the database search engine can use to speed up data retrieval. ✔️ An index in a database is very similar to an index in the back of a book. For example, if you want to reference all pages in a book that discusses a certain topic, you first refer to the index, which lists all the topics alphabetically and are then referred to one or more specific page numbers. ✔️ An index helps to speed up SELECT queries and WHERE clauses, but it slows down data input, with the UPDATE and the INSERT statements. 🔎 When should Indexes be created? - A column contains a wide range of values, and table has millions of rows. - A column does not contain a large number of null values. - One or more columns are frequently used together in a where clause or a join condition. 🔎 When should indexes be avoided? - The table is small. - The columns are not often used as a condition in the query. - The column is ...