SQL：如何在特定时间内找到包含特定字母的所有数据？

Question

I have a table full of city names and I need to find all the citys that contain the letter "a" at least five times. So far I got:

SELECT stadt.Name 
FROM stadt
WHERE stadt.Name LIKE '%a%

But this shows me all the citys with an "a". I need to have a code where I am going to get a table with only citys that have 5 x "a" in its name.

Answer 1

For exactly five a's, you want to check that there are 5 and not 6:

WHERE stadt.Name LIKE '%a%a%a%a%a%' AND
      stadt.Name NOT LIKE '%a%a%a%a%a%a%'

Or, use regular expressions:

WHERE stadt.Name REGEXP '^([^a]*a[^a]*){5}$'