Querying the

Database

MELJUN CORTESMELJUN CORTES

QUERY A question represented in a way

the OO.Org Base can understand Are used to find more item one

record, let you specify the field you want to see in the Data sheet

To access only a subset of your data that can be well defined by a filter condition

Dynaset

Is the set of records resulting from a query or filter

When you edit records in a dynaset, you are actually editing the records in the original table

Creating Query using Design View Open the database file where you

want to create the new query Select Queries object/icon from

Database Pane Click Create Query in Design View Run the query (use Run button)

Querying with Text Exact text dataExamples:

Pop (or 'Pop') Pasig (or 'Pasig')

Using Wildcards Symbols that represent any character

or combination or characters

Wildcards(or wildcard characters) Asterisk (*) – represents any

collection of charactersExample: R*TResult : RT, RAT, RENT, RESET Question Mark (?) – represents any

individual characterExample: R?TResult : RAT, ROT, RIT, RUT

Querying with Numbers Exact numerical value

Default, assumed to be equal to value indicatedOPERATOR – is a sign or symbol that specifies the

type of calculation to perform within an expression

Other comparison operators> greater than< less than>= greater than or equal<= less than or equalNOT not equal toBETWEEN ___ AND ____

Criterion

Are used to select records in queries and filters

Is a set of conditions that must be matched in order for a record to be included in a dynaset

Compound Criteria AND Conditional QueryPlace criteria on the same line(Use CRITERIA row of the design grid)

OR Conditional QueryPlace criteria on separate lines(Use CRITERIA and OR rows of the

design grid)

Expression

Are used to specify criteria in queries perform updates in an action query

Is any combination of mathematical or logical operators, constants, functions, names of fields and properties that evaluates to a single value

JOINING TABLES Select the tables to bring out the

field lists at the upper pane of the Select Query window

Access will draw a line, called join line, between matching fields in the two tables

Select fields either the tables, enter criteria, run query

Access will join the tables automatically

Sorting Data in a Query Sort key – field or fields on which

the records are sorted Primary sort key (or major key) –

more important key when sorting on more than one field

Secondary sort key (or minor key)

Specify sort order in the SORT line of the design grid, e.g., sort key on the left will be the major sort key)