一句SQL，判断char列的值是否组成回文字符串

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我是靠谱客的博主俊秀树叶，这篇文章主要介绍一句SQL，判断char列的值是否组成回文字符串，现在分享给大家，希望可以做个参考。

Table t has 2 columns:
id INT;
value CHAR(1);
Column id starts from 0, increased by 1 each row
Column value is a single character string
Table t has at least 1 row
String s is a palindrome when:
s[i] = s[s.length - i - 1] for i = 0 … (s.length – 1) / 2
E.g.: a, aba, abba.
Q: Write one SQL statement to check if the string composed of value of t ordered by id is a palindrome (case sensitive).
Output “Y” or “N”.
这里写图片描述

with tmp as 
(
    (select (select count(1) from t1)-1-id as id,value from t1)
except
    (select id,value from t1)
)
select 
case when count(1)=0 
then 'Y' else 'N' end 
from tmp;