Step 1: Set the data set. This data set is a certain type in the data dictionary, which can be filtered according to the sql statement, as shown in 1 and 2 in the following figure.
Step 2: Fill in the key name of the field in the main data set in the cell, such as "main.c_businflag", the value and the corresponding setting of the expression reflected in 4 in the figure.
Step 3: The value acquisition code in the key value corresponding to the display value and expression setting is:
busin.select1(C_BUSINNAME, C_BUSINFLAG == value())