Queries help to select information from tables and queries for specific purpose. It select columns from records ,recordes from table/query. You can select, summarize, update, delete, make new table, append records to table using query.

Different types of query :
Select queries: A select query is the most common type of query. It retrieves data from one or more tables and displays the results in a datasheet where you can update the records (with some restrictions). You can also use a select query to group records and calculate sums, counts, averages, and other types of totals.

Parameter queries: A parameter query is a query that when run displays its own dialog box prompting you for information, such as criteria for retrieving records or a value you want to insert in a field. You can design the query to prompt you for more than one piece of information
Crosstab queries: A crosstab query displays summarized values (sums, counts, and averages) from one field in a table and groups them by one set of facts listed down the left side of the datasheet and another set of facts listed across the top of the datasheet.

Action queries (make-table, delete, update, append queries): An action query is a query that makes changes to many records in just one operation. There are four types of action queries: delete, update, append, and make-table.
SQL queries (union, pass-through, data-definition, subquery): An SQL query is a query you create using an SQL statement. Examples of SQL-specific queries are the union query, pass-through query, data-definition query, and subquery.