Firebird 2.1 Language Reference Update

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Internal functions This will return the average weight of the persons listed in FatPeople, excluding those having a weight of -1, since AVG skips NULL data. Presumably, -1 indicates “weight unknown” in this table. A plain AVG(Weight) would include the -1 weights, thus skewing the result. Note In Firebird 1.0.x, where NULLIF is not available, you can accomplish the same with the *nullif external functions. Available in: DSQL, PSQL Added in: 2.0 Changed in: 2.1 OCTET_LENGTH() Description: Gives the length in bytes (octets) of the input string. For multi-byte character sets, this may be less than the number of characters times the “formal” number of bytes per character as found in RDB $CHARACTER_SETS. Note With arguments of type CHAR, this function takes the entire formal string length (e.g. the declared length of a field or variable) into account. If you want to obtain the “logical” byte length, not counting the trailing spaces, right-TRIM the argument before passing it to OCTET_LENGTH. Result type: INTEGER Syntax: OCTET_LENGTH (str) BLOB support: Since Firebird 2.1, this function fully supports text BLOBs of any length and character set. Examples: select octet_length('Hello!') from rdb$database -- returns 6 select octet_length(_iso8859_1 'Grüß di!') from rdb$database -- returns 8: ü and ß take up one byte each in ISO8859_1 select octet_length (cast (_iso8859_1 'Grüß di!' as varchar(24) character set utf8)) from rdb$database -- returns 10: ü and ß take up two bytes each in UTF8 select octet_length (cast (_iso8859_1 'Grüß di!' as char(24) character set utf8)) from rdb$database -- returns 26: all 24 CHAR positions count, and two of them are 2-byte 147
See also: BIT_LENGTH(), CHARACTER_LENGTH Available in: DSQL, PSQL Added in: 2.1 Internal functions OVERLAY() Description: Replaces part of a string with another string. By default, the number of characters removed from the host string equals the length of the replacement string. With the optional fourth argument, the user can specify a different number of characters to be removed. Result type: VARCHAR or BLOB Syntax: Examples: OVERLAY (string PLACING replacement FROM pos [FOR length]) • This function supports BLOBs of any length. Due to a bug, BLOBs containing multi-byte characters – and sometimes even single-byte non-ASCII characters – will cause a “Cannot transliterate character between character sets” error. This bug does not occur in Firebird 2.5. • If string or replacement is a BLOB, the result is a BLOB. Otherwise, the result is a VARCHAR(n) with n the sum of the lengths of string and replacement. • As usual in SQL string functions, pos is 1-based. • If pos is beyond the end of string, replacement is placed directly after string. • If the number of characters from pos to the end of string is smaller than the length of replacement (or than the length argument, if present), string is truncated at pos and replacement placed after it. • The effect of a “FOR 0” clause is that replacement is simply inserted into string. • If any argument is NULL, the result is NULL. • If pos or length is not a whole number, bankers' rounding (round-to-even) is applied, i.e. 0.5 becomes 0, 1.5 becomes 2, 2.5 becomes 2, 3.5 becomes 4, etc. overlay ('Goodbye' placing 'Hello' from 2) -- returns 'GHelloe' overlay ('Goodbye' placing 'Hello' from 5) -- returns 'GoodHello' overlay ('Goodbye' placing 'Hello' from 8) -- returns 'GoodbyeHello' overlay ('Goodbye' placing 'Hello' from 20) -- returns 'GoodbyeHello' overlay ('Goodbye' placing 'Hello' from 2 for 0) -- r. 'GHellooodbye' overlay ('Goodbye' placing 'Hello' from 2 for 3) -- r. 'GHellobye' overlay ('Goodbye' placing 'Hello' from 2 for 6) -- r. 'GHello' overlay ('Goodbye' placing 'Hello' from 2 for 9) -- r. 'GHello' overlay ('Goodbye' placing '' from 4) -- returns 'Goodbye' 148
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Firebird 2.1 Language Reference Upd
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Table of Contents 1. Introduction .
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Firebird 2.1 Language Ref. Update F
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Firebird 2.1 Language Ref. Update A
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Firebird 2.1 Language Ref. Update s
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Chapter 1 Introduction Subject matt
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Chapter 2 Reserved words and keywor
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LOCK LOG LOG10 LPAD MATCHED MATCHIN
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Chapter 3 Available in: DSQL, PSQL
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Example: select name, age, case upp
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Data types and subtypes • Partial
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Added in: 1.0, 1.5, 1.5.1, 2.0, 2.1
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Chapter 5 DDL statements The statem
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With a special attribute (case-sens
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DIFFERENCE FILE parameter Added in:
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CREATE DOMAIN Available in: DSQL, E
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Example: DDL statements create exce
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Syntax: Example: ALTER EXTERNAL FUN
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DDL statements -- the following que
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DDL statements PROCEDURE A stored p
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DDL statements Description: Firebir
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DDL statements NOT NULL in variable
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CREATE GENERATOR Available in: DSQL
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Better alternative: DROP SEQUENCE D
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) DDL statements lastname varchar(2
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USING INDEX subclause Available in:
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ALTER COLUMN: SET DEFAULT Available
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UNIQUE constraints now allow NULLs
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Example: DDL statements create trig
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Multi-action triggers Added in: 1.5
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NOT NULL in variable declarations C
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DDL statements Restriction on recre
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DDL statements got a chance to put
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ORDER BY Available in: DSQL, PSQL A
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DML statements ROWS can also be use
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DML statements COLLATE in variable
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The same call in ESQL (with obligat
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DML statements Description: A SELEC
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DML statements Aggregate functions
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Syntax: Example: Notes: ::= DML
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DML statements select d.dept_no, d.
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DML statements FIRST and SKIP are b
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DML statements select strlen(lastna
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DML statements Description: A natur
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DML statements • Only non-negativ
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Example: DML statements plan (MyTab
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UNIONs in subqueries Changed in: 2.
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Restrictions DML statements • The
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DML statements Description: Limits
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Chapter 7 Available in: DSQL Added
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Transaction control statements If t
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Transaction control statements •
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Chapter 8 PSQL statements PSQL - Pr
Page 108 and 109: PSQL statements • If sql_datatype
Page 110 and 111: Warning PSQL statements If you chan
Page 112 and 113: PSQL statements exception ex_bad_ty
Page 114 and 115: PSQL statements as declare variable
Page 116 and 117: Examples: PSQL statements thoroughl
Page 118 and 119: leave; end end c = 0; PSQL statemen
Page 120 and 121: Chapter 9 Available in: DSQL, PSQL
Page 122 and 123: Changed in: 2.0 Context variables D
Page 124 and 125: Context variables its execution was
Page 126 and 127: Context variables Description: OLD
Page 128 and 129: Chapter 10 Changed in: 2.0 Operator
Page 130 and 131: UNION as subselect Changed in: 2.0
Page 132 and 133: Chapter 11 Aggregate functions Aggr
Page 134 and 135: Chapter 12 Available in: DSQL, PSQL
Page 136 and 137: • If the argument is NULL, NULL i
Page 138 and 139: Result type: INTEGER or BIGINT Synt
Page 140 and 141: Result type: INTEGER Syntax: BIT_LE
Page 142 and 143: Internal functions This gives you c
Page 144 and 145: Available in: DSQL, PSQL Added in:
Page 148 and 149: Example: The equivalent CASE constr
Page 150 and 151: WEEK Bug alert Internal functions M
Page 152 and 153: Added in: 2.1 Internal functions De
Page 154 and 155: Internal functions • If x is nega
Page 156 and 157: Examples: Internal functions lpad (
Page 160 and 161: Internal functions overlay ('Goodby
Page 164 and 165: Internal functions Description: Cre
Page 166 and 167: Internal functions reverse ('Was it
Page 168 and 169: Added in: 2.1 Internal functions De
Page 170 and 171: Syntax: SINH (number) Important Int
Page 174 and 175: Notes: Internal functions • If th
Page 176 and 177: Description: Returns the arc cosine
Page 178 and 179: Declaration: External functions (UD
Page 180 and 181: Library: ib_udf Changed in: 1.0, 2.
Page 182 and 183: Better alternative: Internal functi
Page 184 and 185: External functions (UDFs) Descripti
Page 186 and 187: Syntax: cot (angle) Declaration: Ex
Page 188 and 189: Declaration: External functions (UD
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Page 194 and 195: External functions (UDFs) DECLARE E
Page 196 and 197: See sright. Library: fbudf Added in
Page 198 and 199: Notes: External functions (UDFs) Fo
Page 200 and 201: Syntax: sign (number) Declaration:
Page 202 and 203: Library: fbudf Added in: 1.0 (Win),
Page 204 and 205: Notes: External functions (UDFs) th
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Appendix A: Notes Character set NON
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Table A.1. How TPB settings affect
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Notes A note on CSTRING parameters
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Notes Maximum number of indices in
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Document History DDL statements ::
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Document History Internal functions
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Appendix C: License notice The cont
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Firebird 2.1 Language Reference Update

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