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| The TABULATE Procedure |
In-Database Processing for PROC TABULATE
When the DATA= input data set is stored as a table or view in a database management system (DBMS), the PROC TABULATE procedure can use in-database processing to perform most of its work within the database. In-database processing can provide the advantages of faster processing and reduced data transfer between the database and SAS software.
PROC TABULATE performs in-database processing by using SQL implicit pass-through. The procedure generates SQL queries that are based on the classifications and the statistics that you specify in the TABLE statement. The database executes these SQL queries to construct initial summary tables, which are then transmitted to PROC TABULATE.
If class variables are specified, the procedure creates an SQL GROUP BY clause that represents the n-way type. Only the n-way class tree is generated on the DBMS. The result set that is created when the aggregation query executes in the database is read by SAS into the internal PROC TABULATE data structure.
When SAS format definitions have been deployed in the database, formatting of class variables occurs in the database. If the SAS format definitions have not been deployed in the database, the in-database aggregation occurs on the raw values, and the relevant formats are applied by SAS as the results' set is merged into the PROC TABULATE internal structures. Multi-label formatting is always done by SAS using the initially aggregated result set that is returned by the database.
The following statistics are supported for in-database processing: N, NMISS, MIN, MAX, RANGE, SUM, SUMWGT, CSS, USS, VAR, STD, STDERR, UCLM, LCLM, and CV.
The SQLGENERATION system option or LIBNAME statement option controls whether and how in-database procedures are run inside the database. By default, the in-database procedures are run inside the database when possible. There are many data set options that will prevent in-database processing. For a complete listing, refer to "Overview of In-Database Procedures" in SAS/ACCESS for Relational Databases: Reference.
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