MySQL type of varchar considerations

The problem was found in the work a few days ago: When a field is of type varchar, the field holds values similar to ' 100,200,300 ' and ' 100 ' or ' 100,400 '. When you write a SQL statement, you make such a mistake, such as:

Select Id,provinceid from admin where Provinceid in (' N '); select id, provinceid from admin where Provinceid in ( 100);

You will find that the above 2 SQL query results are not the same, the correct SQL is the 2nd article. Because the field holds a value like ' 100,200,300 ', not a value such as ' 100 ', ' 200 ', ' 300 ', the SQL for 2nd is correct.

MySQL type of varchar considerations