By using a Query.
A database object that retrieves specific data from one or more tables is called a query. Queries are used to extract information from databases based on specified criteria and are essential for data manipulation and reporting purposes.
allows you to ask a question based on one or more tables in a database
The purpose of a query is to extract information from a table or tables, which can be based on some criteria. It can be something simple, like list all names in a table, or something a little more complex, like list all products that are priced over certain amount. A query can be very simple or very complex, depending on your requirements.
This is giving a rating based on some criteria that were set out. You can do a great project and score badly just because you do not meet these criteria.
Criteria-based rating is a method of evaluation where individuals or objects are assessed against established criteria or standards. This approach allows for a more objective and consistent assessment, as judgments are made based on specific guidelines or benchmarks. Criteria-based rating is commonly used in performance appraisals, product reviews, and competitive assessments.
The special character used to represent one or more characters in the criteria area of a query is called a wildcard. In SQL, the asterisk (*) is commonly used as a wildcard to match any sequence of characters, while the question mark (?) can represent a single character. Wildcards are essential for flexible searching and pattern matching in databases.
When you want to extract data from two or more tables, you can use a SQL JOIN query. By using JOIN clauses, you can combine rows from different tables based on a related column between them. This allows you to retrieve data from multiple tables in a single query.
A query by example is where you fill in data that in effect acts like a sample of what you want the query to retrieve. So if you have a set of data of employees and want to show ones that work in a particular department, you would type the name of the department into the query to correspond to the field that shows the department. So in the query, you would have chosen your fields, and in the criteria under the department field you might type something like "Sales", indicating that you want records that have "Sales" in the department field. What you type in acts as an example of the data you want to get. You could use lots of criteria in different ways and build more complex queries, but still using a query by example approach.
A query-based distribution group is a new additional type of distribution group in Exchange 2003. This new type of distribution group provides the same functionality as a standard distribution group; however, instead of specifying static user memberships, a query-based distribution group allows you to use an LDAP query to dynamically build membership in the distribution group (for example All employees with a special group membership). Using query-based distribution groups we can reduce the administration costs dramatically. However a Query-based Distribution Group needs more Server resources like CPU power and RAM.
You apply criteria to queries using the WHERE clause. ex: Select * from tbl_emp This query would fetch all rows from the table tbl_emp Select * from tbl_emp where emp_name = "Rocky" This query would fetch all rows from the table that have employee name as Rocky
You use AND in a query to ensure more than one criteria are met in order for the records to be met. So if you have more than one condition and you want them all to be met, you would use an AND. You would use OR if only some of the conditions need to be met or there are several options on the same field.