QString 字符串拼接与占位符替换：创建 SQL LIKE 查询条件

The given code snippet is using the QString class in Qt to create a string with placeholders (%1 and %2) which will be replaced with values from the iter object.\n\nThe resulting string will be in the format: ""iter.key() like '%2%' and "", where the %1 will be replaced with the value of iter.key() and %2 will also be replaced with iter.key(). \n\nFor example, if iter.key() is ""example"", the resulting string will be: ""example like '%example%' and "".