# Conditions

## Parameter conditions

You should define the conditions that will bypass the normal queries on metadata table. The conditions can be applied on different parameters in "and " or "or" combination.

You must define the **metadata\_name** (the table that will be queried).

You can apply the **condition** that should be verified on parameters in some way:

* \_nn (not null)
* \_nie (not empty)
* \_gt (greater than)
* \_gte (greater equal than)
* \_lt (lower than)
* \_lte (lower equal than)

And you can mix the conditions using "&&" or "||".

```
studenti_id_gt = 20 && studenti_id_lt = 30
studenti_id_nn && join_table_nn
```

The **query\_params** that will be used for the sql query

```
query_params: "studenti_id" 
```

The **sub\_query** to concatenate after **where** in the sql query:

```
sub_query: "uuid in (
select classi_id from studenti_classi where studenti_id = ?
)" 
```

You can define a "separator" to concatenate more conditions.

A complete example:

```
metadata_name: "classi", 
condition: "studenti_id_nn && join_table_nn" 
metadata_name: "classi" 
query_params: "studenti_id" 
sub_query: "uuid in (select classi_id from studenti_classi 
where studenti_id = ?)"
```