characteristics that are in the background to Firebird’s language implementation. 2.1.1. SQL Flavours Distinct subsets of SQL apply to different sectors of activity. The SQL subsets in Firebird’s language implementation delimiting string data. This is contrary to the SQL standard — double quotes are reserved for a distinct syntactic purpose both in standard SQL and in Dialect 3. Double-quoting strings is therefore to instance, the SELECT statement will return all of the rows that match the search criteria unless the DISTINCT option restricts the output to non-duplicated rows. Keywords All words that are included in the

gibt die SELECT -Anweisung alle Zeilen zurück, die den Suchkriterien entsprechen, es sei denn, die DISTINCT -Option beschränkt die Ausgabe auf nicht duplizierte Zeilen. Schlüsselwörter Alle Wörter, die unterstützt: = (Zuordnung) =, <>, <, ⇐, >, >= (Vergeleich) || (Verkettung) BETWEEN, IS [NOT] DISTINCT FROM, IN, ANY | SOME, ALL Teilunterstützung: • Bei diesen tritt ein Fehler auf, wenn das Suchargument des Feldes selbst aus, sondern auf die BLOB-ID. Abgesehen davon gibt es einige Macken: SELECT DISTINCT gibt fälschlicherweise mehrere NULL-Werte zurück, wenn sie vorhanden sind ORDER BY — GROUP

characteristics that are in the background to Firebird’s language implementation. 2.1.1. SQL Flavours Distinct subsets of SQL apply to different sectors of activity. The SQL subsets in Firebird’s language implementation delimiting string data. This is contrary to the SQL standard — double quotes are reserved for a distinct syntactic purpose both in standard SQL and in Dialect 3. Double-quoting strings is therefore to instance, the SELECT statement will return all of the rows that match the search criteria unless the DISTINCT option restricts the output to non-duplicated rows. Keywords All words that are included in the

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 12. SELECT DISTINCT. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 SELECT DISTINCT with wrong NULLS FIRST|LAST ordering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . equality of two expressions with “IS [NOT] DISTINCT FROM”: if ( A is distinct from B ) then... Chapter 2. NULL support in Firebird SQL 7 if ( Buyer1 is not distinct from Buyer2 ) then... Fields, variables

Создание регулярных выражений ................................................................ 76 IS DISTINCT FROM .......................................................................................... [NOT] DISTINCT FROM, IN, ANY|SOME и ALL; • Частичная поддержка для STARTING [WITH], LIKE и CONTAINING. (возникает ошибка, в случае если второй аргумент больше или равен 32 Кб); • SELECT DISTINCT, ORDER используют BLOB ID, а не содержимое самого поля. Это одновременно и хорошо и плохо, кроме того, SELECT DISTINCT ошибочно выдаёт несколько значений NULL, если они присутствуют. GROUP BY ведёт себя странно в том

NULL UNION как подзапрос IN Разрешено использование NULL UNION как подзапрос IS [NOT] DISTINCT FROM NEXT VALUE FOR SIMILAR TO Создание регулярных выражений SOME 13. Агрегатные функции таблице, начиная с Firebird 2.0 7.1 Размещение NULL при сортировке столбцов 12.1 Сравнение IS [NOT] DISTINCT с “=” и “<>” 14.1 Допустимые преобразования типов для функции CAST 14.2 Типы и диапазоны результатов операторов: - = (присвоение); - =, <>, <, <=, >, >= (сравнение); - || (конкатенация); - BETWEEN, IS [NOT] DISTINCT FROM, IN, ANY|SOME и ALL. • Поддержка для STARTING [WITH], LIKE и CONTAINING: - В версиях 2.1–2

explanation is analogous to that of the previous example. The DISTINCT keyword comes to the rescue! Firebird 2 implements a new use of the DISTINCT keyword allowing you to perform (in)equality tests that take semantics are as follows: • Two expressions are DISTINCT if they have different values or if one is NULL and the other isn't; • They are NOT DISTINCT if they have the same value or if both are NULL. operand is NULL, DISTINCT works exactly like the “<>” operator, and NOT DISTINCT like the “=” operator. DISTINCT and NOT DISTINCT always return true or false, never NULL. Using DISTINCT, you can rewrite

identisch zu der im vorherigen Beispiel. Das DISTINCT Schlüsselwort kommt uns hier zu Hilfe! Firebird 2 implementiert eine neue Verwendung des DISTINCT Schlüsselworts, das Ihnen einen Test auf (Un)Gleicheit unterschiedlich (DISTINCT), falls diese unterschiedliche Werte besitzen oder wenn einer der beiden Ausdrücke NULL ist und der Andere nicht; • Zwei Ausdrücke sind nicht unterschiedlich (NOT DISTINCT), falls diese verhält sich DISTINCT wie der „<>“ Operator, und NOT DISTINCT wie der „=“ Operator. DISTINCT und NOT DISTINCT geben immer true oder false zurück und nie NULL. Unter Verwendung von DISTINCT, kann das erste

previous example. Chapter 6. Working with databases 38 The DISTINCT keyword comes to the rescue! Firebird 2 and above implement IS [NOT] DISTINCT allowing you to perform (in)equality tests that take NULL semantics are as follows: • Two expressions are DISTINCT if they have different values or if one is NULL and the other isn’t; • They are NOT DISTINCT if they have the same value or if they are both NULL is NULL, IS DISTINCT works exactly like the “<>” operator, and IS NOT DISTINCT like the “=” operator. IS DISTINCT and IS NOT DISTINCT always return true or false, never NULL. Using DISTINCT, you can rewrite

335544602 table_view_err Only one table allowed for VIEW WITH CHECK OPTION -809 335544603 distinct_err DISTINCT, GROUP or HAVING not permitted for VIEW WITH CHECK OPTION -810 335544605 subquery_err No