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SQL programming
You can use the HCL Informix® implementation of the SQL language to develop applications for Informix database servers.
Guide to SQL: Syntax
The Informix® Guide to SQL: Syntax describes the syntax of the statements, data types, expressions, operators, and built-in functions of the Informix dialect of the SQL language.
Data types and expressions
These topics describe the data types and expressions that Informix®supports.
Literal INTERVAL
The Literal INTERVAL segment specifies a literal INTERVAL value. Use this whenever you see a reference to a literal INTERVAL in a syntax diagram.

SQL programming
You can use the HCL Informix® implementation of the SQL language to develop applications for Informix database servers.
- Guide to SQL: Syntax
  The Informix® Guide to SQL: Syntax describes the syntax of the statements, data types, expressions, operators, and built-in functions of the Informix dialect of the SQL language.
  - Overview of SQL syntax
    These topics provide an overview about how to use the SQL statements, SPL statements, and syntax segments.
  - SQL statements
    This chapter describes the syntax and semantics of SQL statements that are recognized by Informix®.
  - SPL statements
    These topics describe Stored Procedure Language (SPL) statements, which you use to write SPL routines. You can store these routines in the database as user-defined routines (UDRs).
  - Data types and expressions
    These topics describe the data types and expressions that Informix®supports.
    - Scope of Segment Descriptions
    - Use of Segment Descriptions
    - Data type and expression segments
      Data type and expression segments can appear in SQL statements.
    - Collection Subquery
    - Condition
    - Data Type
      The Data Type segment specifies the data type of a column, of a component of a collection, of a field within a ROW type, of a routine parameter, or of a value returned by an expression or by a cast function. Use this segment whenever you see a reference to a data type in a syntax diagram.
    - DATETIME Field Qualifier
      Use a DATETIME Field Qualifier to specify the largest and smallest unit of time in a DATETIME column or value. Use this segment whenever you see a reference to a DATETIME Field Qualifier in a syntax diagram.
    - Expression
    - OLAP window expressions
      You can include On-Line Analytical Processing (OLAP) expressions in a SELECT statement to operate on subsets of the rows in the result set of a query or subquery. You can use OLAP window expressions to examine subsets of the qualifying rows for patterns, trends, or exceptions in the data.
    - INTERVAL Field Qualifier
    - Literal Collection
    - Literal DATETIME
      The Literal DATETIME segment specifies a DATETIME value
    - Literal INTERVAL
      The Literal INTERVAL segment specifies a literal INTERVAL value. Use this whenever you see a reference to a literal INTERVAL in a syntax diagram.
    - Literal Number
    - Literal Row
      The Literal Row segment specifies the syntax for literal values of named and unnamed ROW data types.
    - Quoted String
    - Relational Operator
  - Other syntax segments
    These topics describe syntax segments, which are language elements, such as database object names or optimizer directives, that appear as a subdiagram reference in the syntax diagrams of some SQL or SPL statements.
  - Built-In Routines
  - Appendixes
- Guide to SQL: Reference
  The Informix® Guide to SQL: Reference contains the reference information for the system catalog tables, data types, and environment variables of the HCL Informix dialect of the SQL language, as implemented in HCL Informix. These topics also include information about the stores_demo, sales_demo, and superstore_demo databases that are included with HCL Informix.
- Guide to SQL: Tutorial
  The Informix® Guide to SQL: Tutorial shows how to use basic and advanced structured query language (SQL) to access and manipulate the data in your databases. It discusses the data manipulation language (DML) statements as well as triggers and stored procedure language (SPL) routines, which DML statements often use.

Literal INTERVAL

The Literal INTERVAL segment specifies a literal INTERVAL value. Use this whenever you see a reference to a literal INTERVAL in a syntax diagram.

Syntax

^{(explicit id litint002)
litint002}

Literal INTERVAL

INTERVAL(<Numeric Time Span>) <INTERVAL Field Qualifier>^[]

Numeric Time Span

{ { + | - } { dd [ spacehh [ :mi [ :ss [ .fffff ] ] ] ] | hh [ :mi [ :ss [ .fffff ] ] ] | mi [ :ss [ .fffff ] ] | ss [ .fffff ] | .fffff } | { + | - } { yyyy [ - mo ] | mo } }


Element	Description	Restrictions	Syntax
dd	Number of days	-1010 < dd < 1010	Literal Number
fffff	Fractions of a second	0 fffff 9999	Literal Number
hh	Number of hours	If not first, 0 hh 23	Literal Number
mi	Number of minutes	If not first, 0 mi 59	Literal Number
mo	Number of months	If not first, 0 mo 11	Literal Number
space	Blank space (ASCII 32)	Exactly 1 blank character is required	Literal blank space
ss	Number of seconds	If not first, 0 ss 59	Literal Number
yyyy	Number of years	-10*10 < yyyy* < 10**10	Literal Number

Usage

Unlike DATETIME literals, INTERVAL literals can include the unary plus ( + ) or unary minus ( - ) sign. If you specify no sign, the default is plus.

The precision of the first time unit can be specified by the INTERVAL qualifier. Except for FRACTION, which can have no more than 5 digits of precision, the first time unit can have up to 9 digits of precision, if you specified a nondefault precision in the declaration of the INTERVAL column or variable.

The following examples show literal INTERVAL values:

INTERVAL (3-6) YEAR TO MONTH
INTERVAL (09:55:30.825) HOUR TO FRACTION
INTERVAL (40 5) DAY TO HOUR
INTERVAL (299995.2567) SECOND(6) TO FRACTION(4)

Only the last of these examples has nondefault precision. For the syntax of declaring the precision of INTERVAL data types and the default values for each time unit, refer to INTERVAL Field Qualifier.

¹ See INTERVAL Field Qualifier