## MV_CONCAT

The `MV_CONCAT` function in ES|QL converts a multivalued string expression into a single valued column. It does this by concatenating all values separated by a specified delimiter.

### Examples

Here are a couple of examples of how you can use the `MV_CONCAT` function in your ES|QL queries:

```esql
ROW a=["foo", "zoo", "bar"]
| EVAL j = MV_CONCAT(a, ", ")
```

In this example, the `MV_CONCAT` function is used to concatenate the values in the array `a` with a comma separator. The result is a single string `"foo, zoo, bar"`.

If you need to concatenate non-string columns, you can use the `TO_STRING` function first:

```esql
ROW a=[10, 9, 8]
| EVAL j = MV_CONCAT(TO_STRING(a), ", ")
```

In this case, the numeric values in the array `a` are first converted to strings using the `TO_STRING` function. Then, the `MV_CONCAT` function concatenates these string values with a comma separator. The result is a single string `"10, 9, 8"`.