REPLACE scalar function

Replaces all occurrences of search-string in source-string with replace-string.

The schema is SYSIBM. The SYSFUN version of the REPLACE function continues to be available but it is not sensitive to the database collation.

If the search string is not found in the source string, the search string is returned unchanged. If the Unicode database is defined with a locale-sensitive UCA-based collation and none of the source-string, search-string, or replace-string arguments are defined as FOR BIT DATA or as a binary string, a linguistically correct search is done. Otherwise, the search is done using a binary comparison with no special consideration for multi-byte characters.

source-string

An expression that specifies the source string. The expression must return a value that is a built-in character string, numeric value, DBCLOB value, Boolean value, or datetime value. If the value is:

A numeric, datetime, or CLOB value, it is implicitly cast to VARCHAR before the function is evaluated
A DBCLOB value, it is implicitly cast to VARGRAPHIC before the function is evaluated

The actual length of binary strings cannot exceed 1,048,576 bytes (SQLSTATE 42815).

search-string

An expression that specifies the string to be removed from the source string. The expression must return a value that is a built-in character string, numeric value, DBCLOB value, Boolean value, or datetime value. If the value is:

A numeric, datetime, or CLOB value, it is implicitly cast to VARCHAR before the function is evaluated
A DBCLOB value, it is implicitly cast to VARGRAPHIC before the function is evaluated

The actual length of binary strings cannot exceed 1,048,576 bytes (SQLSTATE 42815).

replace-string

An expression that specifies the replacement string. The expression must return a value that is a built-in character string, numeric value, DBCLOB value, Boolean value, or datetime value. If the value is:

A numeric, datetime, or CLOB value, it is implicitly cast to VARCHAR before the function is evaluated
A DBCLOB value, it is implicitly cast to VARGRAPHIC before the function is evaluated

The actual length of binary strings cannot exceed 1,048,576 bytes (SQLSTATE 42815). If the expression is an empty string or is not specified, nothing replaces the string that is removed from the source string.

All three arguments must have compatible data types.

Result

The data type of the result depends on the data type of the arguments:

If any argument is a BLOB, the result is a BLOB.
If the arguments are binary strings and not BLOB, the result is a VARBINARY.
If the arguments are character strings, the result is a VARCHAR. If any argument is defined as FOR BIT DATA, the result is defined as FOR BIT DATA.
If the arguments are graphic strings, the result is a VARGRAPHIC.

In a Unicode database, if both character strings and graphic strings are used as arguments, then the result data type is based on the string type of the source-string argument. If the source-string argument is a character string type, then the result data type is VARCHAR. If the source-string argument is a graphic string type, then the result data type is VARGRAPHIC.

The string unit of the result is the string unit of source-string. If any argument is defined as FOR BIT DATA, the other arguments cannot be defined with string units of CODEUNITS32.

The string units of the result is the same as the string units of source-string. The length attribute of the result depends on the arguments:

The length attribute of the result is the length attribute of the source-string (with the same string units) in the following cases:
- The replace-string argument is not specified or is specified as an empty string constant.
- The search-string is a constant and the number of bytes in the search-string constant is greater than or equal to:
  - The number of bytes of a constant replace-string.
  - The length attribute of a non-constant character string type replace-string in OCTETS.
  - The length attribute times 2 of a non-constant graphic string type replace-string in double bytes or CODEUNITS16.
  - The length attribute times 4 of a non-constant replace-string in CODEUNITS32.
  - The length attribute of a non-constant binary string type replace-string.
Otherwise, the length attribute of the result is determined by the following calculation depending on the data type of the result (that allows for the smallest possible search-string to be replaced by the largest possible replace-string):
- For VARCHAR with string units of OCTETS:
  - If L1 < = 4000, the length attribute of the result is MIN(4000, (L3*(L1/L2)) + MOD(L1,L2))
  - Otherwise, the length attribute of the result is MIN(32672, (L3*(L1/L2)) + MOD(L1,L2))
- For VARCHAR with string units of CODEUNITS32, the length attribute of the result is MIN(8168, (L3*(L1/L2)) + MOD(L1,L2)).
- For VARGRAPHIC with string units of double bytes or CODEUNITS16:
  - If L1 < = 2000, the length attribute of the result is MIN(2000, (L3*(L1/L2)) + MOD(L1,L2))
  - Otherwise, the length attribute of the result is MIN(16336, (L3*(L1/L2)) + MOD(L1,L2))
- For VARGRAPHIC with string units of CODEUNITS32, the length attribute of the result is MIN(8168, (L3*(L1/L2)) + MOD(L1,L2)).
- For VARBINARY, the length attribute of the result is MIN(32672, (L3*(L1/L2)) + MOD(L1,L2))
- For BLOB, the length attribute of the result is MIN(2G, (L3*(L1/L2)) + MOD(L1,L2))

where the length values for L1, L2, and L3 are given in the following table based on the string units of the result:

Table 1. Length values of L1, L2, and L3
String units of the result	L1	L2	L3
OCTETS (a character string)	Length attribute of `source-string`	One (1) if not a constant, otherwise the actual number of bytes in the constant expressed as a character string type.	If `replace-string` is a constant, the actual number of bytes in the constant expressed as a character string type. If `replace-string` is a character string in OCTETS then the length attribute of `replace-string`. If `replace-string` is a character string or a graphic string in CODEUNITS32, then 4 times the length attribute of `replace-string`. If `replace-string` is a graphic string in double bytes or CODEUNITS16, then 3 times the length attribute of `replace-string`.
CODEUNITS16 or double bytes (a graphic string)	Length attribute of `source-string`	One (1) if not a constant, otherwise the actual number of double bytes or CODEUNITS16 string units in the constant expressed as a graphic string type.	If `replace-string` is a constant, the actual number of double bytes or CODEUNITS16 string units in the constant expressed as a graphic string type. If `replace-string` is a character string in OCTETS or a graphic string in double bytes or CODEUNITS16 then the length attribute of `replace-string`. If `replace-string` is a character string or graphic string in CODEUNITS32 then the 2 times the length attribute of `replace-string`.
CODEUNITS32 (a character string or a graphic string)	Length attribute of `source-string`	One (1) if not a constant, otherwise length attribute of `search-string`.	Length attribute of `replace-string`
Not applicable (a binary string)	Length attribute of source-string	One (1) if not a constant, otherwise the actual number of bytes in the constant expressed as a binary string type.	If replace-string is a constant, the actual number of bytes in the constant expressed as a binary string type. If replace-string is a binary string or character string that is FOR BIT DATA, then the length attribute of replace-string.

If the result is a character string, the length attribute of the result must not exceed the maximum length of the VARCHAR data type in the string units of the result. If the result is a graphic string, the length attribute of the result must not exceed the maximum length of the VARGRAPHIC data type in the string units of the result.

The actual length of the result is the actual length of source-string plus the number of occurrences of search-string that exist in source-string multiplied by the actual length of replace-string minus the actual length of search-string. If the actual length of the result would exceed the length attribute of the result or would exceed 1,048,576 bytes, an error is returned (SQLSTATE 22001).

If the actual length of the replace-string exceeds the maximum for the return data type, an error is returned. If any argument can be null, the result can be null; if any argument is null, the result is the null value.

Examples

Example 1: Replace all occurrences of the letter 'N' in the word 'DINING' with 'VID'.
```
   VALUES CHAR (REPLACE ('DINING', 'N', 'VID'), 10)
```
The result is the string 'DIVIDIVIDG'.
Example 2: In a Unicode database with case-insensitive collation CLDR181_LEN_S1, replace the word 'QUICK' with the word 'LARGE'.
```
VALUES REPLACE ('The quick brown fox', 'QUICK', 'LARGE')
```
The result is the string 'The LARGE brown fox'.