Primitive data types

• String types
• Explicit casting
  • Converting to date and time data types
• Implicit casting
  • Date and time types

DyNumber | A binary representation of a real number with an accuracy of up to 38 digits.
Acceptable values: positive numbers from 1×10-130 up to 1×10126–1, negative numbers from -1×10126–1 to -1×10-130, and 0.
Compatible with the Number type in AWS DynamoDB. It’s not recommended for ydb-native applications. |

Cell size restrictions

The maximum value size for a non-key column cell with any string data type is 8 MB.

Unlike the JSON data type that stores the original text representation passed by the user, JsonDocument uses an indexed binary representation. An important difference from the point of view of semantics is that JsonDocument doesn’t preserve formatting, the order of keys in objects, or their duplicates.

Thanks to the indexed view, JsonDocument lets you bypass the document model using JsonPath without the need to parse the full content. This helps efficiently perform operations from the JSON API, reducing delays and cost of user queries. Execution of queries can be up to several times more efficient depending on the type of load.

Warning

To store numbers (JSON Number) in JsonDocument, as well as for arithmetic operations on them in the , the Double type is used. Precision might be lost when non-standard representations of numbers are used in the source JSON document.

Time zone label for the TzDate, TzDatetime, TzTimestamp types is an attribute that is used:

• In , a timezone component is added to Resource<TM>.

The point in time for these types is stored in UTC, and the timezone label doesn’t participate in any other calculations in any way. For example:

Casting between data types

Explicit casting using :

Casting to numeric types

1 True is converted to 1 and False to 0.
2 Any value other than 0 is converted to , 0 is converted to False.
3 Possible only in the case of a non-negative value.
4 Using the built-in function .

Conversion to other data types

4 Using the built-in function .

Examples

SELECT
CAST(“12345” AS Double), — 12345.0
CAST(1.2345 AS Uint8), — 1
CAST(12345 AS String), — “12345”
CAST(“1.2345” AS Decimal(5, 2)), — 1.23
CAST(“xyz” AS Uint64) IS NULL, — true, because it failed
CAST(-1 AS Uint16) IS NULL, — true, a negative integer cast to an unsigned integer
CAST([-1, 0, 1] AS List<Uint8?>), — [null, 0, 1]
--The item type is optional: the failed item is cast to null.
CAST([“3.14”, “bad”, “42”] AS List), — [3.14, 42]
--The item type is not optional: the failed item has been deleted.
CAST(255 AS Uint8), — 255
CAST(256 AS Uint8) IS NULL — true, out of range

Date and time types