Entering content frame

Predicate (predicate) 

A predicate is specified in a WHERE condition in a statement which is "true", "false", or "unknown". The result is generated by applying the predicate to a specific row in a result table (see result table name) or to a group of rows in a table that was formed by the GROUP clause.

Syntax

<predicate> ::=
  <between_predicate> | <bool_predicate> | <comparison_predicate>
| <default_predicate> | <exists_predicate> | <in_predicate>
| <join_predicate> | <like_predicate> | <null_predicate>
| <quantified_predicate> | <rowno_predicate> | <sounds_predicate>

between_predicate, bool_predicate, comparison_predicate, default_predicate, exists_predicate, in_predicate, join_predicate, like_predicate, null_predicate, quantified_predicate, rowno_predicate, sounds_predicate

Explanation

·        Columns in a table with the same code attribute can be compared.

·        Columns with the different code attributes ASCII and UNICODE can be compared.

·        Columns with the code attribute ASCII or UNICODE can be compared with date values, time values, or timestamp values.

·        LONG columns can only be used in the NULL predicate.

Example table: customer

Selection without a condition:

SELECT city, name, firstname FROM customer

CITY

NAME

FIRSTNAME

New York

Porter

Jenny

Dallas

DATASOFT

?

Los Angeles

Porter

Martin

Los Angeles

Peters

Sally

Hollywood

Brown

Peter

New York

Porter

Michael

New York

Howe

George

Los Angeles

Randolph

Frank

Los Angeles

Peters

Joseph

Los Angeles

Brown

Susan

Los Angeles

Jackson

Anthony

Los Angeles

Adams

Thomas

New York

Griffith

Mark

Los Angeles

TOOLware

?

Hollywood

Brown

Rose

 

Auswahl mit einschränkender Bedingung:

SELECT city, name, firstname FROM customer
WHERE city = 'Los Angeles'

CITY

NAME

FIRSTNAME

Los Angeles

Porter

Martin

Los Angeles

Peters

Sally

Los Angeles

Randolph

Frank

Los Angeles

Peters

Joseph

Los Angeles

Brown

Susan

Los Angeles

Jackson

Anthony

Los Angeles

Adams

Thomas

Los Angeles

TOOLware

?

 

 

Leaving content frame