Editing Data cleaning (section)

==== Verify if value is number in MySQL ====
MySQL: 

* Check if a value is integer e.g. 1234567
** Find the records which the value of `my_column` is numeric values entirely {{code | code = SELECT * FROM `my_table` WHERE `my_column` REGEXP '^[0-9]+$'}}<ref>[http://stackoverflow.com/questions/14343767/mysql-regexp-with-and-numbers-only regex - Mysql REGEXP with . and numbers only - Stack Overflow]</ref><ref>[https://stackoverflow.com/questions/75704/how-do-i-check-to-see-if-a-value-is-an-integer-in-mysql How do I check to see if a value is an integer in MySQL? - Stack Overflow]</ref>

* Find the records which the value of `my_column` is not exactly 8 digits {{code | code = SELECT * FROM my_table WHERE LENGTH(my_column) != 8 OR my_column NOT REGEXP '^[0-9]{8}$'}}
** The `LENGTH()` function checks if the string length is not 8 characters
** The `REGEXP '^[0-9]{8}$'` pattern validates that the value contains exactly 8 digits from start (^) to end ($)
** Using both conditions ensures catching values with correct length but non-numeric characters, as well as incorrect lengths

* Check if a value is integer which may contains comma and dot symbols e.g. 1,234.567 or 3.414
** {{code | code = SELECT * FROM `my_table` WHERE `my_column` REGEXP '^[0-9,\.]+$'}}<ref>[https://community.denodo.com/answers/question/details?questionId=9060g000000XelhAAC&title=How+to+identify+if+values+in+a+column+is+numeric+%28+Function+similar+to+Isnumeric+is+SQL%29 How to identify if values in a column is numeric ( Function similar to Isnumeric is SQL)]</ref>

* Check if a value is NOT integer
** Find the records which the value of `my_column` is '''NOT''' numeric values entirely {{code | code = SELECT * FROM `my_table` WHERE `my_column` NOT REGEXP '^[0-9]+$'}}


If the digit of number is known, the SQL syntax could be more specific
* The {{kbd | key=tax_id}} column is 8 digits only. Find the well-formatted {{kbd | key=tax_id}} records by using {{code | code = SELECT * FROM `tax_id` WHERE `tax_id` REGEXP '^[0-9]{8}$'}}