Given a set of attribute data that contains '0' as a possible value, the user wants to query out the minimum value for the attribute that is not '0'.
The following syntax to be applied to a feature class where four address attributes are being considered (L_F_Add, L_T_Add, R_F_Add, R_T_Add):
Try the following against your dataset. The 999999 value is arbitrary and just needs to be a value higher than your largest attribute value.
MIN(IF(Input.L_F_ADD=0, 999999, Input.L_F_ADD), IF(Input.R_F_ADD=0, 999999, Input.R_F_ADD), IF(Input.L_T_ADD=0, 999999, Input.L_T_ADD), IF(Input.R_T_ADD=0, 999999, Input.R_T_ADD))