Why is my CONCAT function returning an 'invalid number of arguments' error?

Troubleshooting "Concat function is not working - invalid number of arguments" Error

When attempting to concatenate multiple values using the CONCAT function, you may encounter the "invalid number of arguments" error. This typically occurs due to two common mistakes:

1. Incorrect String Delimiters:
   Ensure that you use single quotes (') to wrap strings. In your code, the double quotes (") around the substring expression are incorrect.

   SELECT CONCAT(Name, '('  || SUBSTR(Occupation,1,1) || ')') FROM OCCUPATIONS;

2. Argument Count Exceeding:
   The CONCAT function accepts a maximum of two parameters. Attempting to pass more than two arguments will result in the error. To concatenate multiple values, you can either nest multiple CONCAT functions or use the concatenation operator (||).

   -- Using nested CONCAT
   SELECT CONCAT(CONCAT(Name, '('), SUBSTR(Occupation,1,1), ')') FROM OCCUPATIONS;
   
   -- Using concatenation operator
   SELECT Name || '('  || SUBSTR(Occupation,1,1) || ')' FROM OCCUPATIONS;

Corrected Solution:

The corrected code using the concatenation operator:

SELECT Name || '('  || SUBSTR(Occupation,1,1) || ')' FROM OCCUPATIONS;

This code will concatenate the Name and Occupation columns in the required format and display the results without any errors.

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