You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'SELECT count(*) FROM haonana WHERE unitcode is not null )) t2 FROM
时间: 2023-07-24 10:13:53 浏览: 59
Apologies for the error in the previous response. Here's an updated SQL query to calculate the ratio of the occurrence of fields "a" and "b" together to the occurrence of field "a":
```sql
SELECT a, COUNT(*) AS total_count,
(COUNT(*) / (SELECT COUNT(*) FROM YourTable WHERE a IS NOT NULL)) AS ratio
FROM YourTable
WHERE a = b
GROUP BY a
HAVING ratio > 1/3;
```
In this query, replace "YourTable" with the actual name of your table and "a" with the correct field name.
This query will count the occurrences of fields "a" and "b" together, calculate the ratio of that count to the total count of field "a" (excluding NULL values), and then filter the results to those with a ratio greater than one-third.
Please note that this is a sample query, and you may need to modify it according to your specific table structure and requirements.