> For the complete documentation index, see [llms.txt](https://upsolver.gitbook.io/content/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://upsolver.gitbook.io/content/reference-1/functions-and-operators/operators/conditional/case.md).

# CASE

The standard SQL `CASE` expression has two forms:

[CASE ... WHEN](#case-...-when) 

The simple form searches each `value` expression from left to right until it finds one that equals the given `expression` and then returns the matching `result`.

[CASE WHEN ...](#case-when-...)

The searched form evaluates each Boolean `condition` from left to right until one is true and returns the matching `result`.

## `CASE ... WHEN`

### Syntax

```sql
CASE <expression>
    WHEN <value> THEN <result>
    [ WHEN ... ]
    [ ELSE <result> ]
END
```

### Returns

The `result` for the first `value` found that matches the `expression` is returned.&#x20;

If no match is found, the `result` from the `ELSE` clause is returned if it exists; otherwise `null` is returned.&#x20;

### Examples

#### SQL

```sql
CREATE JOB function_operator_example
    ADD_MISSING_COLUMNS = true	
AS INSERT INTO default_glue_catalog.upsolver_samples.orders_transformed_data 
  MAP_COLUMNS_BY_NAME
    SELECT 
        ordertype,
        (CASE LOWER(ordertype)
            WHEN 'shipping' THEN true
            WHEN 'pickup' THEN false
            ELSE false
        END) AS is_shipped
    FROM default_glue_catalog.upsolver_samples.orders_raw_data 
    WHERE $commit_time BETWEEN run_start_time() AND run_end_time()
    LIMIT 3;
```

#### Query result

| ordertype | is\_shipped |
| --------- | ----------- |
| SHIPPING  | true        |
| shipping  | true        |
| pickup    | false       |

## `CASE WHEN ...`

### Syntax

```sql
CASE
    WHEN <condition> THEN <result>
    [ WHEN ... ]
    [ ELSE <result> ]
END
```

### Returns

The `result` corresponding to the first true `condition` is returned.

If no conditions are true, the `result` from the `ELSE` clause is returned if it exists; otherwise `null` is returned.

### Examples

#### SQL

```sql
CREATE JOB function_operator_example
    ADD_MISSING_COLUMNS = true	
AS INSERT INTO default_glue_catalog.upsolver_samples.orders_transformed_data 
        MAP_COLUMNS_BY_NAME
    SELECT 
        customer_email,
        (CASE
            WHEN customer_email LIKE '%@gmail.com' THEN 'gmail'
            WHEN customer_email LIKE '%@yahoo.com' THEN 'yahoo'
        END) AS email_domain
    FROM default_glue_catalog.upsolver_samples.orders_raw_data 
    WHERE $commit_time BETWEEN run_start_time() AND run_end_time()
    LIMIT 3;
```

#### Query result

| customer\_email                    | email\_domain |
| ---------------------------------- | ------------- |
| <Melissa.Whitej@comcast.net>       | `NULL`        |
| <Patricia.Johnsonfp@hotmail.co.uk> | `NULL`        |
| <Amanda.Thompsonam@gmail.com>      | gmail         |


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