= SAS Sort =

A procedure for sorting and de-duplicating tables.

<<TableOfContents>>

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== Usage ==

To sort a table and write data into a new table, try:

{{{
proc sort data=LIBREF.TABLE1 out=LIBREF.TABLE2;
    by VAR;
run;
}}}

If the '''`OUT`''' option is not specified, the dataset is sorted in place.



=== NoDupKey ===

To remove duplicate cases by `VAR`, use the '''`NODUPKEY`''' option.

{{{
proc sort data=LIBREF.TABLE1 out=LIBREF.TABLE2 nodupkey;
    by VAR;
run;
}}}



=== DupOut ===

To preserve duplicate cases, specify an alternate output on the '''`DUPOUT`''' option. Removed cases will instead be moved into this dataset.

{{{
proc sort data=LIBREF.TABLE1 out=LIBREF.TABLE2 nodupkey dupout=LIBREF.TABLE3;
    by VAR;
run;
}}}

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== Deduplication ==

=== Basic ===

{{{
proc sort data=LIBREF.OLDTABLE out=LIBREF.NEWTABLE nodupkey dupout=LIBREF.REMOVEDCASES
  by ID;
run;
}}}



=== Perfect Duplicates ===

To remove perfect duplicates...
 1. use `_all_` on the `BY` statement
 2. substitute the `NODUPKEY` option with `NODUPRECS`



=== Advanced ===

If there should be a preference between which case is kept, use another `SORT` procedure ''before'' the one specifying `NODUPKEY`.

{{{
proc sort data=LIBREF.OLDTABLE out=LIBREF.TABLE1;
    by ID descending QUALITY DATE;
run;

proc sort data=LIBREF.TABLE1 out=LIBREF.NEWTABLE nodupkey dupout=LIBREF.TABLE2
    by ID;
run;
}}}



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CategoryRicottone