liquibase-core/src/main/java/liquibase/datatype/LiquibaseDataType.java
public String objectToSql(Object value, Database database) {
        if ((value == null) || "null".equals(value.toString().toLowerCase(Locale.US))) {
            return null;
        } else if (value instanceof DatabaseFunction) {
            return functionToSql((DatabaseFunction) value, database);
        } else if (value instanceof Number) {
            return numberToSql((Number) value, database);
        }
        return otherToSql(value, database);
    }
public String objectToSql(Object value, Database database) {
        if ((value == null) || "null".equals(value.toString().toLowerCase(Locale.US))) {
            return null;
        } else if (value instanceof DatabaseFunction) {
            return functionToSql((DatabaseFunction) value, database);
        } else if (value instanceof Number) {
            return numberToSql((Number) value, database);
        }
        return otherToSql(value, database);
    }
Returns the value object in a format to include in SQL. Quote if necessary.