Query – One of the objects in Microsoft Access – It can help users extract data, which meets the criteria defined by them, from a database file. – It must be written in a specific format. – Microsoft Access provides different tools to help users compose a query. – After a query is submitted, Microsoft Access looks up the database and displays the requested data. 11.1Queries The idea of a query

11.1Queries – Although a filter can help us find records that meet certain criteria, we can only obtain one set of filtered records from a table at a time. – The result cannot be further processed. – If we want to store and process the results after execution, queries should be used. The results of filtering cannot be stored for further processing.

11.1Queries – Although a filter can help us find records that meet certain criteria, we can only obtain one set of filtered records from a table at a time. – The result cannot be further processed. – If we want to store and process the results after execution, queries should be used. The results of filtering cannot be stored for further processing.

11.2Creating Queries – Ways to create a query in Microsoft Access: Using Design View Simple Query Wizard Crosstab Query Wizard

Using Design View to Create Queries –In the Design View, users can define queries with selection criteria and sorting method to retrieve and arrange the required data from more than one table. 11.2Creating Queries Extracting data with a query

Criteria of a Query –In a query, criteria can be treated as the rule of retrieving data from a table. –The following table shows the usage of wildcard * and some logical operators which can be used for setting criteria in a query. 11.2Creating Queries

Criteria of a Query 11.2Creating Queries SymbolDescriptionExample *Wildcardlike ‘*D’ like ‘A*’ =Exact match= 100 = ‘Hong Kong’ >Greater than>0 >’A’ >=Greater than or equal to>= 1/1/2007 <Less than< 100 <=Less than or equal to<= 100 <>Not equal to<>’A’ Wildcard and logical operators used for setting criteria in a query

Creating Queries with Simple Query Wizard –The Simple Query Wizard is another tool for creating queries in Microsoft Access. –In the process of generating a query, the Simple Query Wizard prompts users with a series of questions and then generates the required queries based on the responses of users. –The Simple Query Wizard does not allow users to define their own criteria. 11.2Creating Queries

Creating Queries with Simple Query Wizard –The generated queries can be further modified in the Design View. –The Simple Query Wizard can also create a summary query. –A summary query is useful when we want to obtain statistical information such as the total sales amount and the average salary. 11.2Creating Queries

Creating Queries with Simple Query Wizard –The generated queries can be further modified in the Design View. –The Simple Query Wizard can also create a summary query. –A summary query is useful when we want to obtain statistical information such as the total sales amount and the average salary. 11.2Creating Queries