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Oracle/PLSQL: Test a string for a numeric value

Question: In Oracle, I want to know if a string value is numeric only. How can I do this?

Answer: To test a string for numeric characters, you could use a combination of the LENGTH function, TRIM function, and TRANSLATE function built into Oracle.

You can use the following command:

LENGTH(TRIM(TRANSLATE(string1, ' +-.0123456789', ' ')))

string1 is the string value that you are testing

This function will return a null value if string1 is numeric. It will return a value "greater than 0" if string1 contains any non-numeric characters.

For example,

LENGTH(TRIM(TRANSLATE('123b', ' +-.0123456789',' '))); would return 1
LENGTH(TRIM(TRANSLATE('a123b', ' +-.0123456789',' '))); would return 2
LENGTH(TRIM(TRANSLATE('1256.54', ' +-.0123456789',' '))); would return null
LENGTH(TRIM(TRANSLATE ('-56', ' +-.0123456789',' '))); would return null

Learn more about the TRANSLATE function.

Learn more about the LENGTH function.

Learn more about the TRIM function.