YEAR and IIF Functions / Microsoft Access Ira Chinoy / JOUR 772 & 472

Transcription

1 YEAR and IIF Functions / Microsoft Access Ira Chinoy / JOUR 772 & 472 YEAR function: This function allows you to analyze your records by year when you don t have a field in your database listing the year but you do have a field that shows the date. Here is an example using the Hunting.mdb database. SEASON: Year([DEER]![DATE]) The word SEASON (or any other word you choose) is the label for the new column you will see in the answer to your query. The word Year to the right of the colon is the function that extracts the year from the DATE field in the DEER table. If there is only one table in your database, the formula you write can leave out the table name (in this case, DEER), like this: SEASON: Year([DATE]). Also, the Table cell in query grid is left blank when you are creating this formula because you are doing more than simply selecting a field from a particular table. If we wanted to group by the new categories we have created with this formula and count the number of records in each, here s what that query would look like: QUERY: RESULT: 1

2 IIF Function The IIF function also allows you to recode your data, or create categories other than those provided in a particular field. Using the SOFT100K_96CYCLE.mdb database, you might want to see how many large contributions there are at the very high end say, those of $250,000 or more as compared to how many other contributions there are. We could construct a query that would break the records into two parts, as below: the 250K-plus contributions (those with AMOUNT greater than or equal to $250,000) and other contributions (everything else). Grouping by the new and counting up the number or records in each category, the formula would look like this: Here is what we get when we run the query: The formula can be interpreted as follows: LABEL: IIF(Part A, Part B, Part C) where: LABEL is the name we want to give to the column we create. Part A is the statement to be evaluated. Part B is what the formula returns if the statement is true. Part C is what the formula returns if the statement is false. Parts B and C need to be enclosed in quotation marks if the new column is to show a text answer. Parts B and C can also be used to do calculations. Any field names that appear in the formula we construct must be enclosed in brackets: [ ]. If your query uses more than one table and if the name of the field you select appears in more than one table (that is, if two tables have a field with the same name), you need to show both the table name and field name in your formula, each in brackets and joined by an exclamation mark: [TABLE NAME]![FIELD NAME] You will find examples of the way IIF statements are used in the following pages. The first two examples use the CONTRIBS.mdb database (which is the same as the SOFLA.mdb database). The last uses the HUNTING.mdb database. 2

3 Recoding STATE from the CANDIDATES table into two categories: This query creates a new column (CAND_STATE) that breaks the candidates into two groups those from Florida ( FLORIDA ) and those from other states ( OTHER ) and shows how much money each group raised. We have to specify which table has the STATE field we want because there are fields with the same name in both tables. In the Contributions table, the STATE field is the state of the donor. In the Candidates table, the STATE field is the candidate s home state. Here s the answer: 3

4 Recoding homemaker and housewife into one category ( at home ) This formula also uses the operator IN to look for entries that appear in a list enclosed in parentheses: OCCUPCODE: IIF([Contributions]![OCCUPATION] In ("homemaker","housewife"),"at home","other") 4

5 Using the IIF function to recode data with a wildcard in HUNTING.MDB LOF: IIf([CAUSE] Like "*line of fire*","line of fire","other") or LOF: IIf([DEER!CAUSE] Like "*line of fire*","line of fire","other") This is the same query, but without including the CAUSE field, so we can get a total count of the LINE OF FIRE cases: rev 2/08 5