And data query, if you have superior data showed superior, if there is no data will show their superiors,
For example:
Is filled with 1, county, city filled with, provincial filled with it according to the provincial data
Is filled with 2, county, city not fill, fill at the provincial level or according to the provincial data
3, provided at the county level, the city filled with, provincial did not fill in it according to the municipal data

CodePudding user response:

Test data is given script, the database version, and needs to display the data of the sample

CodePudding user response:

SELECT IFNULL ((SELECT T2. To display the contents of the FROM TABLE_NAME T2 WHERE & lt;

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