I had two problems.
my table has a column called basePrice. It is a decimal (15,3) in mysql. The thing is in yii 1.1.x, I can use compare and the operator is automatically handled. However, I did not see the equivalent in yii2. can someone help?
the other problem is that this field, basePrice will be set to 0 every time I make a filter to other field. this is annoying since will effect the result of the filtered gridview.
Thanks in advance for your help.