Assume you are getting the selected row values from Table1.
Need to apply filter for Table based on your selected Table1 row,
So in the below example "_oTable" is your table2.
try this,
onSearch: function(oEvent) {
var comboBoxValue = this.byId("oComboBox").getValue(),
oBinding = this._oTable.getBinding("items"),
oFilter;
if (comboBoxValue || comboBoxValue === "") {
this._oTable.setShowOverlay(false);
oFilter = new sap.ui.model.Filter("SupplierName", "EQ", comboBoxValue);
oBinding.filter([oFilter]);
}
}