. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 9. Conditional statements and loops . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . behaviour of NULL in Firebird SQL, points out common pitfalls and shows you how to deal safely with expressions that contain NULL or may resolve to NULL. If you only need a quick reference to refresh your memory (Firebird 2+) In Firebird 2 and higher only, you can test for the null-encompassing equality of two expressions with “IS [NOT] DISTINCT FROM”: if ( A is distinct from B ) then... Chapter 2. NULL support in

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 4.1. Expressions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 4.1.3. Conditional Expressions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 4.1.4. NULL in Expressions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 230 6.1.14. Common Table Expressions (“WITH … AS … SELECT”) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231 6.2. INSERT

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69 4.1. Expressions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77 4.1.3. Conditional Expressions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80 4.1.4. NULL in Expressions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 311 6.1.16. Common Table Expressions (“WITH … AS … SELECT”) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 312 6.2. INSERT

но ключевые слова: ACTIVE, AFTER, ASC, ASCENDING, AUTO, BEFORE, COLLATION, COMMITTED, COMPUTED, CONDITIONAL, CONTAINING, CSTRING, DATABASE, DESC, DESCENDING, DESCRIPTOR, DO, DOMAIN, ENTRY_POINT, EXCEPTION 21 Руководство по языку SQL ASC ASCENDING AUTO BEFORE CASCADE COLLATION COMMITTED COMPUTED CONDITIONAL CONTAINING CSTRING DATABASE DESC DESCENDING DESCRIPTOR DO DOMAIN ENTRY_POINT EXCEPTION EXIT FILE Доступно: DSQL, PSQL Добавлено: 2.1 Описание: Общие табличные выражения (Common Table Expressions), сокращённо CTE, могут быть описаны как виртуальные таблицы или представления, определенных

SHADOW Назначение: Создание теневой копии. Синтаксис: CREATE SHADOW sh_num [AUTO | MANUAL] [CONDITIONAL] 'filepath' [LENGTH [=] num [PAGE[S]]] []; ::= FILE 'filepath' обычным образом без осуществления копирования в данную теневую копию. Если указано ключевое слово CONDITIONAL, то система будет пытаться создать новую теневую копию. чтобы заменить потерянную. Это не всегда Общие табличные выражения CTE ("WITH ... AS ... SELECT") Общие табличные выражения (Common Table Expressions), сокращённо CTE, описаны как виртуальные таблицы или представления, определённые в преамбуле основного

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 300 6.1.15. Common Table Expressions (“WITH … AS … SELECT”) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 301 6.2. INSERT Datenbank erstellen Verfügbar in DSQL, ESQL Syntax CREATE SHADOW [{AUTO | MANUAL}] [CONDITIONAL] 'filepath' [LENGTH [=] num [PAGE[S]]] [ ...] ::= FILE aus dem Datenbankheader gelöscht und die Datenbank funktioniert normal weiter. Wenn die Option CONDITIONAL gesetzt wurde, versucht das System, einen neuen Schatten zu erstellen, um den verlorenen zu ersetzen

........... 3 NULL dans les expressions ..................................................................................................................... 3 Expressions retournant NULL ........... ............................................................................. 4 NULL dans des expressions booléennes ................................................................................... Firebird SQL, pointe les chausse-trappe habituelles et vous montre comment travailler avec des expressions qui contiennent NULL ou peuvent avoir un résultat NULL. Si vous voulez une référence rapide pour

which resolves integer/integer division to a float quotient, you will need to alter any affected expressions to use a float or scaled numeric type for either dividend, divisor, or both. For example, the would cause an error and halt execution.) See also the section below, Expressions involving NULL, about concatenating in expressions involving NULL. Double-quoted identifiers Before the SQL-92 standard double-quoting of all identifiers by default. Try to choose a tool which makes double-quoting optional. Expressions involving NULL In SQL, NULL is not a value. It is a condition, or state, of a data item, in which

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 6.4.3. Expressions involving NULL. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . which resolves integer/integer division to a float quotient, you will need to alter any affected expressions to use a float or scaled numeric type for either dividend, divisor, or both. For example, the would cause an error and halt execution.) See also the section below, Expressions involving NULL�, about concatenating in expressions involving NULL. Chapter 6. Working with databases 36 Double-quoted

integer by an integer .......................................................................... 19 Expressions involving NULL ............................................................................... length limit for a char or a varchar (32 Kb). See also the note below, Expressions involving NULL, about concatenating in expressions involving Firebird 1.0 Quick Start Guide 18 NULL. Division of an which resolves integer/integer division to a float quotient, you will need to alter any affected expressions to use a float or scaled numeric type for either dividend, di- visor, or both. For example, the