SPSS Programming and Data Management, 4th Edition: A Guide for ...

27GettingDataintoSPSS• Left outer join. All records from the first table are included regardless of the criteriaused to match records.• Right outer join. Essentially the opposite of a left outer join. So, the appropriateone to use is basically a matter of the order in which the tables are specified in theSQL SELECT clause.ExampleIn the previous two examples, all of the data resided in a single database table. Butwhat if the data were divided between two tables? This example merges data from twodifferent tables: one containing demographic information for survey respondents andone containing survey responses.*access_multtables1.sps.GET DATA /TYPE=ODBC /CONNECT='DSN=MS Access Database;DBQ=C:\examples\data\dm_demo.mdb;'+'DriverId=25;FIL=MS Access;MaxBufferSize=2048;PageTimeout=5;'/SQL ='SELECT * FROM DemographicInformation, SurveyResponses'' WHERE DemographicInformation.ID=SurveyResponses.ID'.EXECUTE.• The SELECT clause specifies all fields from both tables.• The WHERE clause matches records from the two tables based on the value of theID field in both tables. Any records in either table without matching ID values inthe other table are excluded.• The result is an inner join in which only records with matching ID values in bothtables are included in the active dataset.ExampleIn addition to one-to-one matching, as in the previous inner join example, you can alsomerge tables with a one-to-many matching scheme. For example, you could match atable in which there are only a few records representing data values and associateddescriptive labels with values in a table containing hundreds or thousands of recordsrepresenting survey respondents.In this example, we read data from an SQL Server database, using an outer join toavoid omitting records in the larger table that don’t have matching identifier values inthe smaller table.*sqlserver_outer_join.sps.