解释SELECT distinct ICD10 FROM tb_acc_importhistory WHERE not REGEXP_LIKE(ICD10,'[\u4e00-\u9fa5]');

这是一条SQL查询语句，查询的是tb_acc_importhistory表中ICD10字段的不重复值，且ICD10字段不包含中文字符的记录。

其中，REGEXP_LIKE是一个正则表达式函数，用于判断一个字符串是否符合某种正则表达式的模式。[\u4e00-\u9fa5]代表中文字符的unicode编码范围，所以这个正则表达式的含义是判断ICD10字段是否包含中文字符。not关键字表示取反，所以not REGEXP_LIKE(ICD10,'[\u4e00-\u9fa5]')的含义是ICD10字段不包含中文字符。

相关问题

SELECT distinct ICD10 FROM tb_acc_importhistory WHERE not REGEXP_LIKE(ICD10,'[\u4e00-\u9fa5]');

As an AI language model, I cannot access your database. However, the SQL query you provided selects distinct ICD10 codes from the "tb_acc_importhistory" table where the ICD10 code does not contain any Chinese characters. The regular expression used in this query ensures that only non-Chinese characters are present in the ICD10 code.

select a.id from tb_plan_month a where a.status = 40 and a.is_del = 0 and a.id not in (SELECT b.month_id from tb_plan_day b where b.spaces5='2023-06-01' and b.is_del = 0) 请帮我优化

可以尝试以下两种方法来优化这个查询：

1. 使用 `NOT EXISTS` 替代 `NOT IN` 子查询：

SELECT a.id 
FROM tb_plan_month a 
WHERE a.status = 40 
  AND a.is_del = 0 
  AND NOT EXISTS (
    SELECT 1 
    FROM tb_plan_day b 
    WHERE b.month_id = a.id 
      AND b.spaces5 = '2023-06-01' 
      AND b.is_del = 0
  );

2. 将 `NOT IN` 子查询改为 `LEFT JOIN`：

SELECT a.id 
FROM tb_plan_month a 
LEFT JOIN (
    SELECT DISTINCT month_id 
    FROM tb_plan_day 
    WHERE spaces5 = '2023-06-01' 
      AND is_del = 0
) b ON a.id = b.month_id 
WHERE a.status = 40 
  AND a.is_del = 0 
  AND b.month_id IS NULL;

这两种方法都可以避免使用 `NOT IN` 子查询，从而提高查询性能。请根据实际情况选择适合您的方法。