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A search condition is the criteria 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.
search-condition: expression comparison-operator expression | expression IS [ NOT ] NULL | expression [ NOT ] BETWEEN expression AND expression | expression [ NOT ] IN ( expression, ... ) | expression [ NOT ] IN ( subquery ) | expression [ NOT ] { ANY | ALL } ( subquery ) | expression [ NOT ] EXISTS ( subquery ) | expression [ NOT ] LIKE ( pattern ) | NOT search-condition | search-condition AND search-condition | search-condition OR search-condition | ( search-condition IS [ NOT ] {TRUE | FALSE | UNKNOWN }
comparison-operator : = | > | < | >= | <= | <> | != | !< | !>
The different types of search conditions supported by UltraLite include:
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.