如何編寫一個mysql查詢以滿足以下要求？

Question

我有一個名爲tbl_loans的表，它具有字段loan_number。

貸款號碼的0001，0023，0045所以我想找出是否有貸款數長度大於4個數字或大於4號

下有沒有簡單的方法來找出這個？關於長度的MySQL函數

Answer 1

SELECT * FROM tbl_loans WHERE LENGTH(loan_number)<>4; 

更多信息（和其他字符串函數）： http://dev.mysql.com/doc/refman/5.1/en/string-functions.html#function_length

Answer 2

SELECT * FROM tbl_loans WHERE LENGTH(loan_number) < 4 

Answer 3

SELECT * FROM tbl_loans WHERE LENGTH(loan_number) <>4 

或

SELECT * FROM tbl_loans WHERE LENGTH(loan_number) !=4 

或

SELECT * FROM tbl_loans WHERE LENGTH(loan_number)<4 OR LENGTH(loan_number)>4