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SQL Anywhere 11.0.0 » UltraLite - Database Management and Reference » UltraLite SQL Reference » UltraLite SQL elements reference » Expressions in UltraLite

 

Search conditions in UltraLite

Specifies a search condition for a WHERE clause, a HAVING clause, an ON phrase in a join, or an IF expression. A search condition is also called a predicate.

Syntax
search-condition:
 expression compare expression
| expression IS [ NOT ] { NULL | TRUE | FALSE | UNKNOWN }
| expression [ NOT ] BETWEEN expression AND expression
| expression [ NOT ] IN ( expression, ... )
| expression [ NOT ] IN ( subquery )
| expression [ NOT ] { ANY | ALL } ( subquery ) 
| expression [ NOT ] EXISTS ( subquery ) 
| NOT search-condition
| search-condition AND search-condition
| search-condition OR search-condition
| ( search-condition )
Parameters
compare:
= | > | < | >= | <= | <> | != | !< | !>
Remarks

In UltraLite, search conditions can appear in the:

  • WHERE clause
  • HAVING clause
  • ON phrase
  • SQL queries

Search conditions can be used to choose a subset of the rows from a table in a FROM clause in a SELECT statement, or in expressions such as an IF or CASE to select specific values. In UltraLite, every condition evaluates as one of three states: TRUE, FALSE, or UNKNOWN. When combined, these states are referred to as three-valued logic. The result of a comparison is UNKNOWN if either value being compared is the NULL value. Search conditions are satisfied only if the result of the condition is TRUE.

The different types of search conditions supported by UltraLite include:

These conditions are discussed in separate sections that follow.

Note

Subqueries form an important class of expression that is used in many search conditions.

See also

Comparison operators
Logical operators
ALL conditions
ANY conditions
BETWEEN conditions
EXISTS conditions
IN conditions