sql - Count right word from a specific variable

Question

How should I be able to count the word "asdf" in the variable aaa with value "asdf_dd_adf34asdf_sdf"?

DECLARE @aaa varchar;

SET @aaa = 'asdf_dd_adf34asdf_sdf';

Answer 1

如果删除单词的出现次数，然后除以单词的长度，请计算有多少字符消失：

(len(aaa) - len(replace(aaa, 'asdf', ''))) / len('asdf')