def json_array(on_null: JsonOnNull = JsonOnNull.ABSENT, *args) -> Expression:
"""
Builds a JSON array string from a list of values.
This function returns a JSON string. The values can be arbitrary expressions. The `on_null`
behavior defines how to treat `NULL` values.
Elements which are created from another JSON construction function call (`json_object`,
`json_array`) are inserted directly rather than as a string. This allows building nested JSON
structures.
Examples:
::
>>> json_array() # '[]'
>>> json_array(JsonOnNull.NULL, 1, "2") # '[1,"2"]'
>>> # Expressions as values
>>> json_array(JsonOnNull.NULL, col("orderId"))
>>> json_array(JsonOnNull.NULL, null_of(DataTypes.STRING())) # '[null]'
>>> json_array(JsonOnNull.ABSENT, null_of(DataTypes.STRING())) # '[]'
>>> json_array(JsonOnNull.NULL, json_array(JsonOnNull.NULL, 1)) # '[[1]]'
.. seealso:: :func:`~pyflink.table.expressions.json_object`
"""
return _varargs_op("jsonArray", *(on_null._to_j_json_on_null(), *args))
def json_object(on_null: JsonOnNull = JsonOnNull.NULL, *args) -> Expression:
"""
Builds a JSON object string from a list of key-value pairs.
`args` is an even-numbered list of alternating key/value pairs. Note that keys must be
non-`NULL` string literals, while values may be arbitrary expressions.
This function returns a JSON string. The `on_null` behavior defines how to treat `NULL` values.
Values which are created from another JSON construction function call (`json_object`,
`json_array`) are inserted directly rather than as a string. This allows building nested JSON
structures.
Examples:
::
>>> json_object() # '{}'
>>> json_object(JsonOnNull.NULL, "K1", "V1", "K2", "V2") # '{"K1":"V1","K2":"V2"}'
>>> # Expressions as values
>>> json_object(JsonOnNull.NULL, "orderNo", col("orderId"))
>>> json_object(JsonOnNull.NULL, "K1", null_of(DataTypes.STRING())) # '{"K1":null}'
>>> json_object(JsonOnNull.ABSENT, "K1", null_of(DataTypes.STRING())) # '{}'
>>> # '{"K1":{"K2":"V"}}'
>>> json_object(JsonOnNull.NULL, "K1", json_object(JsonOnNull.NULL, "K2", "V"))
.. seealso:: :func:`~pyflink.table.expressions.json_array`
"""
return _varargs_op("jsonObject", *(on_null._to_j_json_on_null(), *args))
def json_object(on_null: JsonOnNull = JsonOnNull.NULL, *args) -> Expression:
"""
Builds a JSON object string from a list of key-value pairs.
`args` is an even-numbered list of alternating key/value pairs. Note that keys must be
non-`NULL` string literals, while values may be arbitrary expressions.
This function returns a JSON string. The `on_null` behavior defines how to treat `NULL` values.
Examples:
::
>>> json_object() # '{}'
>>> json_object(JsonOnNull.NULL, "K1", "V1", "K2", "V2") # '{"K1":"V1","K2":"V2"}'
>>> # Expressions as values
>>> json_object(JsonOnNull.NULL, "orderNo", col("orderId"))
>>> json_object(JsonOnNull.NULL, "K1", null_of(DataTypes.STRING())) # '{"K1":null}'
>>> json_object(JsonOnNull.ABSENT, "K1", null_of(DataTypes.STRING())) # '{}'
>>> # '{"K1":{"K2":"V"}}'
>>> json_object(JsonOnNull.NULL, "K1", json_object(JsonOnNull.NULL, "K2", "V"))
"""
return _varargs_op("jsonObject", *(on_null._to_j_json_on_null(), *args))
def json_array_agg(on_null: JsonOnNull, item_expr) -> Expression:
"""
Builds a JSON object string by aggregating items into an array.
Item expressions can be arbitrary, including other JSON functions. If a value is `NULL`, the
`on_null` behavior defines what to do.
This function is currently not supported in `OVER` windows, unbounded session windows, or hop
windows.
Examples:
::
>>> # '["Apple","Banana","Orange"]'
>>> orders.select(json_array_agg(JsonOnNull.NULL, col("product")))
"""
return _binary_op("jsonArrayAgg", on_null._to_j_json_on_null(), item_expr)
def json_object_agg(on_null: JsonOnNull, key_expr: Union[str, Expression[str]],
value_expr) -> Expression:
"""
Builds a JSON object string by aggregating key-value expressions into a single JSON object.
The key expression must return a non-nullable character string. Value expressions can be
arbitrary, including other JSON functions. If a value is `NULL`, the `on_null` behavior defines
what to do.
Note that keys must be unique. If a key occurs multiple times, an error will be thrown.
This function is currently not supported in `OVER` windows.
Examples:
::
>>> # '{"Apple":2,"Banana":17,"Orange":0}'
>>> orders.select(json_object_agg(JsonOnNull.NULL, col("product"), col("cnt")))
"""
return _ternary_op("jsonObjectAgg", on_null._to_j_json_on_null(), key_expr,
value_expr)