Welcome
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.
Condition
Comparison Conditions (Boolean Expressions)
Comparison conditions are often called Boolean expressions because they return a TRUE or FALSE result.

HCL Informix® V14.10 documentation
Welcome to the documentation for HCL Informix® 14.10 and related client tools and products. The current fix pack level of Informix is 14.10.xC13.
Product overview
HCL Informix® is a fast and scalable database server that manages traditional relational, object-relational, and dimensional databases. Its small footprint and self-managing capabilities are suited to embedded data-management solutions.
Installing
These topics describe how to install HCL Informix® database servers, client products, and DataBlade® modules.
Administering
In addition to administering the database server, you can tune performance, replicate data, and archive data.
Migrating and upgrading
You can upgrade to the 14.10 release of HCL Informix® or migrate from other database servers to Informix. Upgrading is an in-place migration method that uses your existing hardware and operating system software. Some changes to the Informix database server can affect upgrading from a previous release.
Client APIs and tools
You can use the HCL Informix® implementation of client APIs to develop applications for Informix database servers.
Embedding Informix®
When you embed HCL Informix®, you can use enterprise-class high-availability and high performance with embeddability features such as easy programmability, a small disk and memory footprint, and silent deployment.
Extending Informix®
Beyond standard relational database objects, HCL Informix® can be extended to handle specialized data types, access methods, routines, and other objects. Informix includes many built-in extensions that are fully integrated in the database server. Informix also provides DataBlade® modules, which are packages of extended database objects for a particular purpose and that are installed separately from the database server. Alternatively, you can create your own user-defined objects for Informix.
Data warehousing
In addition to designing and implementing Informix® dimensional databases, you can use tools to create data warehouse applications and optimize your data warehouse queries.
Designing databases
The first step in creating a relational database is to construct a data model, which is a precise, complete definition of the data you want to store. After you prepare your data model, you must implement it as a database and tables. To implement your data model, you first select a data type for each column and then you create a database and tables and populate the tables with data. You can also implement fragmentation strategies and control access to your data.
JSON compatibility
You can use the popular JSON-oriented query language created by MongoDB to interact with data stored in HCL Informix®.
Security
You can secure your Informix® database server and the data that is stored in your Informix databases. You can encrypt data, secure connections, control user privileges and access, and audit data security.
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
      - Comparison Conditions (Boolean Expressions)
        Comparison conditions are often called Boolean expressions because they return a TRUE or FALSE result.
      - Column Name
      - Quotation Marks in Conditions
      - Relational-Operator Condition
        A relational operator compares two expressions quantitatively.
      - BETWEEN Condition
        Use the BETWEEN condition to test whether the value of a numeric, character, or time expression is within a specified range.
      - IN Condition
      - IS NULL and IS NOT NULL Conditions
      - Trigger-Type Boolean Operator
      - LIKE and MATCHES Condition
        A LIKE or MATCHES condition tests for matching character strings.
      - Stand-Alone Condition
      - Condition with Subquery
      - NOT Operator
      - Conditions with AND or OR
        You can combine simple conditions with the logical operators AND or OR to form complex conditions.
    - 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
  These topics contain 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
  This publication 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.
Troubleshooting HCL Informix®
Several troubleshooting techniques, tools, and resources are available for resolving problems that you encounter in your HCL Informix® database server environment.
Informix PDF guides

Comparison Conditions (Boolean Expressions)

Comparison conditions are often called Boolean expressions because they return a TRUE or FALSE result.

Six kinds of Boolean operators can specify a comparison condition:

Relational operators
[NOT] BETWEEN AND operators
[NOT] IN operators
IS [NOT] NULL operators
Trigger-type operators
[NOT] LIKE or MATCHES operators

Their syntax is summarized in this diagram and explained in the sections that follow.

Comparison Conditions

Notes:

¹ See Expression
² See Relational Operator
³ Informix® extension
⁴ See IN Condition
⁵ SPL trigger routines only
⁶ See Trigger-Type Boolean Operator


Element	Description	Restrictions	Syntax
char	An ASCII character to be the escape character in the quoted string. Single ( ' ) and double ( " ) quotation marks are not valid as char.	See ESCAPE with LIKE and ESCAPE with MATCHES	Quoted String
column	Name of a column (or a field of a ROW-type column) whose data value is compared to NULL, to string, or to another column	Can be qualified by the identifier, synonym, or alias of a table or view	See Column Name
expression	An SQL expression that returns a single value	Must return a single value	Expression
string	A string delimited by single ( ' ) or double ( " ) quotation marks	Both delimiters must be identical	See Quoted String

The following sections describe the different types of comparison conditions:

For a discussion of comparison conditions in the context of the SELECT statement, see Using a Condition in the WHERE Clause.

Warning: A literal DATE or DATETIME value in a comparison condition should specify 4 digits for the year. When you specify a 4-digit year, the DBCENTURY environment variable has no effect on the result. When you specify a 2-digit year, DBCENTURY can affect how the database server interprets the comparison condition, which might not work as you intended. For more information about DBCENTURY, see the Informix® Guide to SQL: Reference.