Expressions passed to this function must have the following data types:
- source_string = CHAR, VARCHAR, or CLOB
- search_string = CHAR, VARCHAR, or CLOB
- position = INTEGER, BIGINT, or NUMBER
- occurrence = INTEGER, BIGINT, or NUMBER
You can also pass arguments with data types that can be converted to the above types using the implicit data type conversion rules that apply to UDFs.
The UDF implicit type conversion rules are more restrictive than the implicit type conversion rules normally used by Vantage. If an argument cannot be converted to the required data type following the UDF implicit conversion rules, it must be explicitly cast.
For details, see “Compatible Types” in Teradata Vantage™ - SQL External Routine Programming , B035-1147 .
If a match is found, the function returns the position (starting from 1) in the source_string for the match; otherwise the function returns 0. If any of the input arguments are NULL, the function returns NULL.