docs/sql-manual/sql-functions/bitmap-functions/bitmap-to-base64.md

---
{
    "title": "BITMAP_TO_BASE64",
    "language": "en"
}
---

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## bitmap_to_base64

### description
#### Syntax

`VARCHAR BITMAP_TO_BASE64(BITMAP input)`

Convert an input BITMAP to a base64 string. If input is null, return null. Since BE config item `enable_set_in_bitmap_value` will change the format of bitmap value in memory, it also affect the result of this function.
Since the order of elements in the bitmap cannot be guaranteed, there is no guarantee that the base64 results generated by bitmaps with the same content are always the same, but the bitmap after bitmap_from_base64 decoding can be guaranteed to be the same.

### example

```
mysql> select bitmap_to_base64(null);
+------------------------+
| bitmap_to_base64(NULL) |
+------------------------+
| NULL                   |
+------------------------+

mysql> select bitmap_to_base64(bitmap_empty());
+----------------------------------+
| bitmap_to_base64(bitmap_empty()) |
+----------------------------------+
| AA==                             |
+----------------------------------+

mysql> select bitmap_to_base64(to_bitmap(1));
+--------------------------------+
| bitmap_to_base64(to_bitmap(1)) |
+--------------------------------+
| AQEAAAA=                       |
+--------------------------------+

mysql> select bitmap_to_base64(bitmap_from_string("1,9999999"));
+---------------------------------------------------------+
| bitmap_to_base64(bitmap_from_string("1,9999999"))       |
+---------------------------------------------------------+
| AjowAAACAAAAAAAAAJgAAAAYAAAAGgAAAAEAf5Y=                |
+---------------------------------------------------------+

```

### keywords

    BITMAP_TO_BASE64,BITMAP