When writing SQL code, you may find yourself needing to reference a Boolean field. Here are three different approaches of writing code that all reference both True and False using SQL.

The first approach uses 4D process variables set to True and False; then in SQL code, those process variables are referenced as the true and false values:

` using a process variable C_BOOLEAN(false_b;true_b) false_b:=False true_b:=True Begin SQL SELECT * FROM Table_1 WHERE (       Field_2 = :true_b AND       Field_3 = :false_b       ) INTO :LBox1 End SQL

The second approach uses the SQL function CAST to cast a number to a boolean value.

` using CAST with a number Begin SQL SELECT * FROM Table_1 WHERE (       Field_2 = CAST(1 AS BOOLEAN) AND       Field_3 = CAST(0 AS BOOLEAN)       ) INTO :LBox2 End SQL

The above snippet of code uses the CAST function in SQL to CAST the number 1 as True and CAST the number 0 as False.

The third approach also uses the SQL function CAST, but this example uses a string instead of a number.

` using CAST with a string Begin SQL SELECT * FROM Table_1 WHERE (       Field_2 = CAST('true' AS BOOLEAN) AND       Field_3 = CAST('false' AS BOOLEAN)       ) INTO :LBox3 End SQL

The above snippet of code uses the CAST function in SQL to CAST the string 'true' as True and CAST the string 'false' as False.

Each of these examples shows a different way of returning records which are "True" for Field_2 and "False" for Field_3.