Collation order for character data

Collation is the process of sorting character strings according to some order. The database server or the client application can perform collation.

The collating order affects the following tasks in SQL SELECT statements:
  • Logical predicates in the WHERE clause 
    SELECT * FROM tab1 WHERE col1 > 'bob'
SELECT * FROM tab1 WHERE site BETWEEN 'abc' AND 'xyz'
  • Sorted data that the ORDER BY clause creates 
    SELECT * FROM tab1 ORDER BY col1
  • Comparisons in MATCHES and LIKE clauses 
    SELECT * FROM tab1 WHERE col1 MATCHES 'a1*'
SELECT * FROM tab1 WHERE col1 LIKE 'dog'
SELECT * FROM tab1 WHERE col1 MATCHES 'abc[a-z]'

For more information about how the database locale can affect the SELECT statement, see Collation order in SELECT statements.

HCL Informix® database servers support two collation methods:
  • Code-set order (the first-to-last order of characters in the code set)
  • Localized order (if the locale defines a localized order)