Correctly compare numeric field values

modules/store/src/main/resources/db/migration/h2/V1.21.0__cast_function.sql

@@ -0,0 +1,12 @@
+DROP ALIAS IF EXISTS CAST_TO_NUMERIC;
+CREATE ALIAS CAST_TO_NUMERIC AS '
+import java.text.*;
+import java.math.*;
+@CODE
+BigDecimal castToNumeric(String s) throws Exception {
+  try { return new BigDecimal(s); }
+  catch (Exception e) {
+    return null;
+  }
+}
+'

modules/store/src/main/resources/db/migration/mariadb/V1.21.0__cast_function.sql

@@ -0,0 +1,5 @@
+-- Create a function to cast to a numeric, if an error occurs return null
+-- Could not get it working with decimal type, so using double
+create or replace function CAST_TO_NUMERIC (s char(255))
+returns double deterministic
+return cast(s as double);

modules/store/src/main/resources/db/migration/postgresql/V1.21.0__cast_function.sql

@@ -0,0 +1,9 @@
+-- Create a function to cast to a numeric, if an error occurs return null
+create or replace function CAST_TO_NUMERIC(text) returns numeric as $$
+begin
+    return cast($1 as numeric);
+exception
+    when invalid_text_representation then
+        return null;
+end;
+$$ language plpgsql immutable;