Table of Contents

Acknowledgments....................................................................................................... vii

1 Introduction to Dates and Times in SAS........................................................ 1

1.1 How Does It Work? (January 1, 1960 and Midnight as Zero)............................. 2

1.2 Internal Representation (Storage as Integers or Real Numbers)............................ 2

1.3 External Representation (Basic Format Concepts)................................................ 3

1.4 Date and Time as Numeric Constants in SAS..................................................... 3

1.5 System Options Related to Dates...................................................................... 5

1.6 Length and Numeric Requirements for Date, Time, and Datetime....................... 12

2 Displaying SAS Date, Time, and Datetime Values as Dates and Times
as We Know Them........................................................................................ 15

2.1 How Do I Use a Format?............................................................................... 16

2.2 So Just How Many Built-in Formats Are There for Dates and Times?.................... 18

2.3 A Quick Note About Date Formats, Justification, and ODS................................ 19

2.4 Detailed Discussion of Each Format................................................................ 19

2.4.1 Date Formats..................................................................................... 19

2.4.2 Time Formats..................................................................................... 43

2.4.3 Datetime Formats............................................................................... 47

2.5 Creating Custom Date Formats Using the VALUE Statement of
PROC FORMAT........................................................................................... 54

2.6 Creating Custom Date Formats Using the PICTURE Statement of
PROC FORMAT........................................................................................... 56

2.7 The PUT() Function and Formats..................................................................... 60

3 Converting Dates and Times into SAS Date, Time,
and Datetime Values..................................................................................... 63

3.1 Avoiding the Two-Digit Year Trap.................................................................. 64

3.2 Using Informats............................................................................................ 65

3.3 The INFORMAT Statement............................................................................. 66

3.3.1 Using Informats with the INPUT Statement............................................. 66

3.3.2 Informats with the INPUT() Function...................................................... 67

3.3.3 When the Informat Does Not Match the Data Being Read...................... 68

3.4 Listing and Discussion of Informats.................................................................. 70

3.4.1 Date Informats................................................................................... 70

3.4.2 Time Informats................................................................................... 75

3.4.3 Datetime Informats............................................................................. 77

3.4.4 ANYDT and Its Variants...................................................................... 77

4 Date and Time Functions............................................................................... 85

4.1 Current Date and Time Functions.................................................................... 86

4.2 Extracting Pieces from SAS Date, Time, and Datetime Values............................ 86

4.3 Creating Dates, Times, and Datetimes from Numbers....................................... 89

4.4 Calculating Intervals..................................................................................... 93

4.4.1 Calculating Elapsed Time with DATDIF() and YRDIF()............................ 93

4.4.2 The Basics of SAS Intervals.................................................................. 96

4.4.3 The Interval Calculation Functions: INTCK and INTNX............................ 98

5 Deeper into Dates and Times with SAS..................................................... 107

5.1 Macro Variables and Dates........................................................................ 108

5.1.1 Automatic Macro Variables............................................................... 108

5.1.2 Putting Dates into Titles..................................................................... 109

5.1.4 Using %SYSFUNC() to Create Dates, Times, and Datetimes in
Macro Variables.............................................................................. 110

5.1.4 Using CALL SYMPUT() and SYMGET() with Dates, Times, and
Datetimes........................................................................................ 111

5.2 Shifting SAS Date and Time Intervals............................................................ 113

5.3 Graphing Dates........................................................................................ 122

5.4 The Basics of PROC EXPAND...................................................................... 127

5.4.1 Capabilities of PROC EXPAND.......................................................... 127

5.4.2 Using PROC EXPAND to Convert to a Higher Frequency....................... 129

5.4.3 Using PROC EXPAND to Convert to a Lower Frequency........................ 130

5.4.4 Using PROC EXPAND to Interpolate Missing Values............................. 132

5.4.5 The OBSERVED= Option for the CONVERT Statement in
PROC EXPAND............................................................................... 133

5.5 International Date, Time, and Datetime Formats and Informats........................ 136

5.5.1 “EUR” Formats and Informats............................................................ 137

5.5.2 “NL” Formats................................................................................... 140

5.5.3 Specific Language Date Formats and Informats................................... 143

5.6 Other Software and Their Dates (Excel, Oracle, DB2).................................... 144

Appendix A Quick Reference Guide to SAS Date, Time, and Datetime
Formats............................................................................................... 145

Index.................................................................................................................... 147