8.3. String Functions

8.3.1. ASCII_CHAR()

Available inDSQL, PSQL

Possible name conflictYES → Read details

Result typeCHAR(1) CHARACTER SET NONE

Syntax 

  |ASCII_CHAR (code)

Table 8.30. ASCII_CHAR Function Parameter
ParameterDescription

code

An integer within the range from 0 to 255

Returns the ASCII character corresponding to the number passed in the argument.

☝
Important

  • If you are used to the behaviour of the ASCII_CHAR UDF, which returns an empty string if the argument is 0, please notice that the internal function correctly returns a character with ASCII code 0 here.

8.3.2. ASCII_VAL()

Available inDSQL, PSQL

Possible name conflictYES → Read details

Result typeSMALLINT

Syntax 

  |ASCII_VAL (ch)

Table 8.31. ASCII_VAL Function Parameter
ParameterDescription

ch

A string of the [VAR]CHAR data type or a text BLOB with the maximum size of 32,767 bytes

Returns the ASCII code of the character passed in.

  • If the argument is a string with more than one character, the ASCII code of the first character is returned.

  • If the argument is an empty string, 0 is returned.

  • If the argument is NULL, NULL is returned.

  • If the first character of the argument string is multi-byte, an error is raised. (A bug in Firebird 2.1 - 2.1.3 and 2.5.0 causes an error to be raised if any character in the string is multi-byte. This is fixed in versions 2.1.4 and 2.5.1.)

8.3.3. BIT_LENGTH()

Available inDSQL, PSQL

Result typeINTEGER

Syntax 

  |BIT_LENGTH (string)

Table 8.32. BIT_LENGTH Function Parameter
ParameterDescription

string

An expression of a string type

Gives the length in bits of the input string. For multi-byte character sets, this may be less than the number of characters times 8 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 (i.e. the declared length of a field or variable) into account. If you want to obtain the logical bit length, not counting the trailing spaces, right-TRIM the argument before passing it to BIT_LENGTH.

BLOB supportSince Firebird 2.1, this function fully supports text BLOBs of any length and character set.

8.3.3.1. BIT_LENGTH Examples

   |select bit_length('Hello!') from rdb$database
   |-- returns 48
   | 
   |select bit_length(_iso8859_1 'Grüß di!') from rdb$database
   |-- returns 64: ü and ß take up one byte each in ISO8859_1
   | 
   |select bit_length
   |  (cast (_iso8859_1 'Grüß di!' as varchar(24) character set utf8))
   |from rdb$database
   |-- returns 80: ü and ß take up two bytes each in UTF8
   | 
   |select bit_length
   |  (cast (_iso8859_1 'Grüß di!' as char(24) character set utf8))
   |from rdb$database
   |-- returns 208: all 24 CHAR positions count, and two of them are 16-bit

See alsoSection 8.3.9, “OCTET_LENGTH()”, Section 8.3.4, “CHAR_LENGTH(), CHARACTER_LENGTH()”

8.3.4. CHAR_LENGTH(), CHARACTER_LENGTH()

Available inDSQL, PSQL

Result typeINTEGER

Syntax 

  |  CHAR_LENGTH (string)
  || CHARACTER_LENGTH (string)

Table 8.33. CHAR[ACTER]_LENGTH Function Parameter
ParameterDescription

string

An expression of a string type

Gives the length in characters of the input string.

ⓘ
Note

  • With arguments of type CHAR, this function returns the formal string length (i.e. the declared length of a field or variable). If you want to obtain the logical length, not counting the trailing spaces, right-TRIM the argument before passing it to CHAR[ACTER]_LENGTH.

  • BLOB support: Since Firebird 2.1, this function fully supports text BLOBs of any length and character set.

8.3.4.1. CHAR_LENGTH Examples

   |select char_length('Hello!') from rdb$database
   |-- returns 6
   | 
   |select char_length(_iso8859_1 'Grüß di!') from rdb$database
   |-- returns 8
   | 
   |select char_length
   |  (cast (_iso8859_1 'Grüß di!' as varchar(24) character set utf8))
   |from rdb$database
   |-- returns 8; the fact that ü and ß take up two bytes each is irrelevant
   | 
   |select char_length
   |  (cast (_iso8859_1 'Grüß di!' as char(24) character set utf8))
   |from rdb$database
   |-- returns 24: all 24 CHAR positions count

See alsoSection 8.3.3, “BIT_LENGTH()”, Section 8.3.9, “OCTET_LENGTH()”

8.3.5. HASH()

Available inDSQL, PSQL

Result typeBIGINT

Syntax 

  |HASH (string)

Table 8.34. HASH Function Parameter
ParameterDescription

string

An expression of a string type

Returns a hash value for the input string. This function fully supports text BLOBs of any length and character set.

8.3.6. LEFT()

Available inDSQL, PSQL

Result typeVARCHAR or BLOB

Syntax 

  |LEFT (string, length)

Table 8.35. LEFT Function Parameters
ParameterDescription

string

An expression of a string type

length

Integer expression. Defines the number of characters to return

Returns the leftmost part of the argument string. The number of characters is given in the second argument.

  • This function fully supports text BLOBs of any length, including those with a multi-byte character set.

  • If string is a BLOB, the result is a BLOB. Otherwise, the result is a VARCHAR(n) with n the length of the input string.

  • If the length argument exceeds the string length, the input string is returned unchanged.

  • If the length argument 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.

See alsoSection 8.3.14, “RIGHT()”

8.3.7. LOWER()

Available inDSQL, ESQL, PSQL

Possible name conflictYES → Read details below

Result type(VAR)CHAR or BLOB

Syntax 

  |LOWER (string)

Table 8.36. LOWER Function ParameterS
ParameterDescription

string

An expression of a string type

Returns the lower-case equivalent of the input string. The exact result depends on the character set. With ASCII or NONE for instance, only ASCII characters are lowercased; with OCTETS, the entire string is returned unchanged. Since Firebird 2.1 this function also fully supports text BLOBs of any length and character set.

ⓘ
Name Clash

Because LOWER is a reserved word, the internal function will take precedence even if the external function by that name has also been declared. To call the (inferior!) external function, use double-quotes and the exact capitalisation, as in "LOWER"(string).

8.3.7.1. LOWER Examples

  |select Sheriff from Towns
  |  where lower(Name) = 'cooper''s valley'

See alsoSection 8.3.18, “UPPER()”

8.3.8. LPAD()

Available inDSQL, PSQL

Possible name conflictYES → Read details

Result typeVARCHAR or BLOB

Syntax 

  |LPAD (str, endlen [, padstr])

Table 8.37. LPAD Function Parameters
ParameterDescription

str

An expression of a string type

endlen

Output string length

padstr

The character or string to be used to pad the source string up to the specified length. Default is space (' ')

Left-pads a string with spaces or with a user-supplied string until a given length is reached.

  • This function fully supports text BLOBs of any length and character set.

  • If str is a BLOB, the result is a BLOB. Otherwise, the result is a VARCHAR(endlen).

  • If padstr is given and equals '' (empty string), no padding takes place.

  • If endlen is less than the current string length, the string is truncated to endlen, even if padstr is the empty string.

ⓘ
Note

In Firebird 2.1-2.1.3, all non-BLOB results were of type VARCHAR(32765), which made it advisable to cast them to a more modest size. This is no longer the case.

🛑
Warning

When used on a BLOB, this function may need to load the entire object into memory. Although it does try to limit memory consumption, this may affect performance if huge BLOBs are involved.

8.3.8.1. LPAD Examples

  |lpad ('Hello', 12)               -- returns '       Hello'
  |lpad ('Hello', 12, '-')          -- returns '-------Hello'
  |lpad ('Hello', 12, '')           -- returns 'Hello'
  |lpad ('Hello', 12, 'abc')        -- returns 'abcabcaHello'
  |lpad ('Hello', 12, 'abcdefghij') -- returns 'abcdefgHello'
  |lpad ('Hello', 2)                -- returns 'He'
  |lpad ('Hello', 2, '-')           -- returns 'He'
  |lpad ('Hello', 2, '')            -- returns 'He'

See alsoSection 8.3.15, “RPAD()”

8.3.9. OCTET_LENGTH()

Available inDSQL, PSQL

Result typeINTEGER

Syntax 

  |OCTET_LENGTH (string)

Table 8.38. OCTET_LENGTH Function Parameter
ParameterDescription

string

An expression of a string type

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 (i.e. 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.

BLOB supportSince Firebird 2.1, this function fully supports text BLOBs of any length and character set.

8.3.9.1. OCTET_LENGTH 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

See alsoSection 8.3.3, “BIT_LENGTH()”, Section 8.3.4, “CHAR_LENGTH(), CHARACTER_LENGTH()”

8.3.10. OVERLAY()

Available inDSQL, PSQL

Result typeVARCHAR or BLOB

Syntax 

  |OVERLAY (string PLACING replacement FROM pos [FOR length])

Table 8.39. OVERLAY Function Parameters
ParameterDescription

string

The string into which the replacement takes place

replacement

Replacement string

pos

The position from which replacement takes place (starting position)

length

The number of characters that are to be overwritten

OVERLAY() overwrites part of a string with another string. By default, the number of characters removed from (overwritten in) the host string equals the length of the replacement string. With the optional fourth argument, a different number of characters can be specified for removal.

  • This function supports BLOBs of any length.

  • 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.

🛑
Warning

When used on a BLOB, this function may need to load the entire object into memory. This may affect performance if huge BLOBs are involved.

8.3.10.1. OVERLAY Examples

   |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'
   |overlay ('Goodbye' placing '' from 4 for 3)  -- returns 'Gooe'
   |overlay ('Goodbye' placing '' from 4 for 20) -- returns 'Goo'
   | 
   |overlay ('' placing 'Hello' from 4)          -- returns 'Hello'
   |overlay ('' placing 'Hello' from 4 for 0)    -- returns 'Hello'
   |overlay ('' placing 'Hello' from 4 for 20)   -- returns 'Hello'

See alsoSection 8.3.12, “REPLACE()”

8.3.11. POSITION()

Available inDSQL, PSQL

Result typeINTEGER

Syntax 

  |  POSITION (substr IN string)
  || POSITION (substr, string [, startpos])

Table 8.40. POSITION Function Parameters
ParameterDescription

substr

The substring whose position is to be searched for

string

The string which is to be searched

startpos

The position in string where the search is to start

Returns the (1-based) position of the first occurrence of a substring in a host string. With the optional third argument, the search starts at a given offset, disregarding any matches that may occur earlier in the string. If no match is found, the result is 0.

ⓘ
Note

  • The optional third argument is only supported in the second syntax (comma syntax).

  • The empty string is considered a substring of every string. Therefore, if substr is '' (empty string) and string is not NULL, the result is:

    • 1 if startpos is not given;

    • startpos if startpos lies within string;

    • 0 if startpos lies beyond the end of string.

    Notice: A bug in Firebird 2.1 - 2.1.3 and 2.5.0 causes POSITION to always return 1 if substr is the empty string. This is fixed in 2.1.4 and 2.5.1.

  • This function fully supports text BLOBs of any size and character set.

🛑
Warning

When used on a BLOB, this function may need to load the entire object into memory. This may affect performance if huge BLOBs are involved.

8.3.11.1. POSITION Examples

  |position ('be' in 'To be or not to be')   -- returns 4
  |position ('be', 'To be or not to be')     -- returns 4
  |position ('be', 'To be or not to be', 4)  -- returns 4
  |position ('be', 'To be or not to be', 8)  -- returns 17
  |position ('be', 'To be or not to be', 18) -- returns 0
  |position ('be' in 'Alas, poor Yorick!')   -- returns 0

See alsoSection 8.3.16, “SUBSTRING()”

8.3.12. REPLACE()

Available inDSQL, PSQL

Result typeVARCHAR or BLOB

Syntax 

  |REPLACE (str, find, repl)

Table 8.41. REPLACE Function Parameters
ParameterDescription

str

The string in which the replacement is to take place

find

The string to search for

repl

The replacement string

Replaces all occurrences of a substring in a string.

  • This function fully supports text BLOBs of any length and character set.

  • If any argument is a BLOB, the result is a BLOB. Otherwise, the result is a VARCHAR(n) with n calculated from the lengths of str, find and repl in such a way that even the maximum possible number of replacements won’t overflow the field.

  • If find is the empty string, str is returned unchanged.

  • If repl is the empty string, all occurrences of find are deleted from str.

  • If any argument is NULL, the result is always NULL, even if nothing would have been replaced.

🛑
Warning

When used on a BLOB, this function may need to load the entire object into memory. This may affect performance if huge BLOBs are involved.

8.3.12.1. REPLACE Examples

  |replace ('Billy Wilder',  'il', 'oog') -- returns 'Boogly Woogder'
  |replace ('Billy Wilder',  'il',    '') -- returns 'Bly Wder'
  |replace ('Billy Wilder',  null, 'oog') -- returns NULL
  |replace ('Billy Wilder',  'il',  null) -- returns NULL
  |replace ('Billy Wilder', 'xyz',  null) -- returns NULL (!)
  |replace ('Billy Wilder', 'xyz', 'abc') -- returns 'Billy Wilder'
  |replace ('Billy Wilder',    '', 'abc') -- returns 'Billy Wilder'

See alsoSection 8.3.10, “OVERLAY()”, Section 8.3.16, “SUBSTRING()”, Section 8.3.11, “POSITION()”, Section 8.3.4, “CHAR_LENGTH(), CHARACTER_LENGTH()”

8.3.13. REVERSE()

Available inDSQL, PSQL

Result typeVARCHAR

Syntax 

  |REVERSE (string)

Table 8.42. REVERSE Function Parameter
ParameterDescription

string

An expression of a string type

Returns a string backwards.

8.3.13.1. REVERSE Examples

  |reverse ('spoonful')            -- returns 'lufnoops'
  |reverse ('Was it a cat I saw?') -- returns '?was I tac a ti saW'
☞
Tip

This function comes in very handy if you want to group, search or order on string endings, e.g. when dealing with domain names or email addresses:

  |create index ix_people_email on people
  |  computed by (reverse(email));
  | 
  |select * from people
  |  where reverse(email) starting with reverse('.br');

8.3.14. RIGHT()

Available inDSQL, PSQL

Possible name conflictYES → Read details

Result typeVARCHAR or BLOB

Syntax 

  |RIGHT (string, length)

Table 8.43. RIGHT Function Parameters
ParameterDescription

string

An expression of a string type

length

Integer. Defines the number of characters to return

Returns the rightmost part of the argument string. The number of characters is given in the second argument.

  • This function supports text BLOBs of any length, but has a bug in versions 2.1 - 2.1.3 and 2.5.0 that makes it fail with text BLOBs larger than 1024 bytes that have a multi-byte character set. This has been fixed in versions 2.1.4 and 2.5.1.

  • If string is a BLOB, the result is a BLOB. Otherwise, the result is a VARCHAR(n) with n the length of the input string.

  • If the length argument exceeds the string length, the input string is returned unchanged.

  • If the length argument 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.

🛑
Warning

When used on a BLOB, this function may need to load the entire object into memory. This may affect performance if huge BLOBs are involved.

See alsoSection 8.3.6, “LEFT()”, Section 8.3.16, “SUBSTRING()”

8.3.15. RPAD()

Available inDSQL, PSQL

Possible name conflictYES → Read details

Result typeVARCHAR or BLOB

Syntax 

  |RPAD (str, endlen [, padstr])

Table 8.44. RPAD Function Parameters
ParameterDescription

str

An expression of a string type

endlen

Output string length

endlen

The character or string to be used to pad the source string up to the specified length. Default is space (' ')

Right-pads a string with spaces or with a user-supplied string until a given length is reached.

  • This function fully supports text BLOBs of any length and character set.

  • If str is a BLOB, the result is a BLOB. Otherwise, the result is a VARCHAR(endlen).

  • If padstr is given and equals '' (empty string), no padding takes place.

  • If endlen is less than the current string length, the string is truncated to endlen, even if padstr is the empty string.

ⓘ
Note

In Firebird 2.1-2.1.3, all non-BLOB results were of type VARCHAR(32765), which made it advisable to cast them to a more modest size. This is no longer the case.

🛑
Warning

When used on a BLOB, this function may need to load the entire object into memory. Although it does try to limit memory consumption, this may affect performance if huge BLOBs are involved.

8.3.15.1. RPAD Examples

  |rpad ('Hello', 12)               -- returns 'Hello       '
  |rpad ('Hello', 12, '-')          -- returns 'Hello-------'
  |rpad ('Hello', 12, '')           -- returns 'Hello'
  |rpad ('Hello', 12, 'abc')        -- returns 'Helloabcabca'
  |rpad ('Hello', 12, 'abcdefghij') -- returns 'Helloabcdefg'
  |rpad ('Hello', 2)                -- returns 'He'
  |rpad ('Hello', 2, '-')           -- returns 'He'
  |rpad ('Hello', 2, '')            -- returns 'He'

See alsoSection 8.3.8, “LPAD()”

8.3.16. SUBSTRING()

Available inDSQL, PSQL

Result typesVARCHAR or BLOB

Syntax 

   |SUBSTRING ( <substring-args> )
   | 
   |<substring-args> ::=
   |    str FROM startpos [FOR length]
   |  | str SIMILAR <similar-pattern> ESCAPE <escape>
   | 
   |<similar-pattern> ::=
   |  <similar-pattern-R1>
   |  <escape> " <similar-pattern-R2> <escape> "
   |  <similar-pattern-R3>

Table 8.45. SUBSTRING Function Parameters
ParameterDescription

str

An expression of a string type

startpos

Integer expression, the position from which to start retrieving the substring

length

The number of characters to retrieve after the startpos

similar-pattern

SQL regular expression pattern to search for the substring

escape

Escape character

Returns a string’s substring starting at the given position, either to the end of the string or with a given length, or extracts a substring using an SQL regular expression pattern.

If any argument is NULL, the result is also NULL.

🛑
Warning

When used on a BLOB, this function may need to load the entire object into memory. Although it does try to limit memory consumption, this may affect performance if huge BLOBs are involved.

8.3.16.1. Positional SUBSTRING

In its simple, positional form (with FROM), this function returns the substring starting at character position startpos (the first position being 1). Without the FOR argument, it returns all the remaining characters in the string. With FOR, it returns length characters or the remainder of the string, whichever is shorter.

The function fully supports binary and text BLOBs of any length, and with any character set. If str is a BLOB, the result is also a BLOB. For any other argument type, the result is a VARCHAR.

For non-BLOB arguments, the width of the result field is always equal to the length of str, regardless of startpos and length. So, substring('pinhead' from 4 for 2) will return a VARCHAR(7) containing the string 'he'.

Example 

  |insert into AbbrNames(AbbrName)
  |  select substring(LongName from 1 for 3) from LongNames

8.3.16.2. Regular Expression SUBSTRING

In the regular expression form (with SIMILAR), the SUBSTRING function returns part of the string matching an SQL regular expression pattern. If no match is found, NULL is returned.

The SIMILAR pattern is formed from three SQL regular expression patterns, R1, R2 and R3. The entire pattern takes the form of R1 || '<escape>"' || R2 || '<escape>"' || R3, where <escape> is the escape character defined in the ESCAPE clause. R2 is the pattern that matches the substring to extract, and is enclosed between escaped double quotes (<escape>", e.g. #" with escape character #). R1 matches the prefix of the string, and R3 the suffix of the string. Both R1 and R3 are optional (they can be empty), but the pattern must match the entire string. In other words, it is not sufficient to specify a pattern that only finds the substring to extract.

☞
Tip

The escaped double quotes around R2 can be compared to defining a single capture group in more common regular expression syntax like PCRE. That is, the full pattern is equivalent to R1(R2)R3, which must match the entire input string, and the capture group is the substring to be returned.

ⓘ
Note

If any one of R1, R2, or R3 is not a zero-length string and does not have the format of an SQL regular expression, then an exception is raised.

The full SQL regular expression format is described in Syntax: SQL Regular Expressions

Examples 

  |substring('abcabc' similar 'a#"bcab#"c' escape '#')  -- bcab
  |substring('abcabc' similar 'a#"%#"c' escape '#')     -- bcab
  |substring('abcabc' similar '_#"%#"_' escape '#')     -- bcab
  |substring('abcabc' similar '#"(abc)*#"' escape '#')  -- abcabc
  |substring('abcabc' similar '#"abc#"' escape '#')     -- <null>

See alsoSection 8.3.11, “POSITION()”, Section 8.3.6, “LEFT()”, Section 8.3.14, “RIGHT()”, Section 8.3.4, “CHAR_LENGTH(), CHARACTER_LENGTH()”, SIMILAR TO

8.3.17. TRIM()

Available inDSQL, PSQL

Result typeVARCHAR or BLOB

Syntax 

  |TRIM ([<adjust>] str)
  | 
  |<adjust> ::=  {[<where>] [what]} FROM
  | 
  |<where> ::=  BOTH | LEADING | TRAILING

Table 8.46. TRIM Function Parameters
ParameterDescription

str

An expression of a string type

where

The position the substring is to be removed from — BOTH | LEADING | TRAILING. BOTH is the default

what

The substring that should be removed (multiple times if there are several matches) from the beginning, the end, or both sides of the input string str. By default it is space (' ')

Removes leading and/or trailing spaces (or optionally other strings) from the input string. Since Firebird 2.1 this function fully supports text BLOBs of any length and character set.

ⓘ
Note

  • If str is a BLOB, the result is a BLOB. Otherwise, it is a VARCHAR(n) with n the formal length of str.

  • Since Firebird 3.0, the maximum size of what — if a `BLOB — was increased to 4GB, in previous versions the value of what could not exceed 32767 bytes.

🛑
Warning

When used on a BLOB, this function may need to load the entire object into memory. This may affect performance if huge BLOBs are involved.

8.3.17.1. TRIM Examples

   |select trim ('  Waste no space   ') from rdb$database
   |-- returns 'Waste no space'
   | 
   |select trim (leading from '  Waste no space   ') from rdb$database
   |-- returns 'Waste no space   '
   | 
   |select trim (leading '.' from '  Waste no space   ') from rdb$database
   |-- returns '  Waste no space   '
   | 
   |select trim (trailing '!' from 'Help!!!!') from rdb$database
   |-- returns 'Help'
   | 
   |select trim ('la' from 'lalala I love you Ella') from rdb$database
   |-- returns ' I love you El'
   | 
   |select trim ('la' from 'Lalala I love you Ella') from rdb$database
   |-- returns 'Lalala I love you El'

8.3.18. UPPER()

Available inDSQL, ESQL, PSQL

Result type(VAR)CHAR or BLOB

Syntax 

  |UPPER (str)

Table 8.47. UPPER Function Parameter
ParameterDescription

str

An expression of a string type

Returns the upper-case equivalent of the input string. The exact result depends on the character set. With ASCII or NONE for instance, only ASCII characters are uppercased; with OCTETS, the entire string is returned unchanged. Since Firebird 2.1 this function also fully supports text BLOBs of any length and character set.

8.3.18.1. UPPER Examples

  |select upper(_iso8859_1 'Débâcle')
  |from rdb$database
  |-- returns 'DÉBÂCLE' (before Firebird 2.0: 'DéBâCLE')
  | 
  |select upper(_iso8859_1 'Débâcle' collate fr_fr)
  |from rdb$database
  |-- returns 'DEBACLE', following French uppercasing rules

See alsoSection 8.3.7, “LOWER()”