You can use the CREATE VIEW statement to create a view. A view is a virtual table based on the SELECT statement. Views can be used to define new virtual sources (type conversion, column conversion, virtual column, etc.), split long code, and so on.
CREATE VIEW View name AS SELECT Clause
Create a view named MyView:
CREATE VIEW MyView AS SELECT s1.time_, s1.client_ip, s1.uri, s1.protocol_version, s2.status_code, s2.date_ FROM KafkaSource1 AS s1, KafkaSource2 AS s2 WHERE s1.time_ = s2.time_ AND s1.client_ip = s2.client_ip;
In calculations, due to a large amount of data and the matching requirements of function method types, TINYINT, SMALLINT, REAL and other types must be used. However, when a Stream Connector input type does not meet the requirements, a virtual view can be defined as a new source using the CREATE VIEW statement in conjunction with CAST() type conversion function .
In the following example, a view named KafkaSource2 is defined to convert a status_code column in the KafkaSource1 source from BIGINT type to VARCHAR type:
CREATE VIEW KafkaSource2 AS SELECT `time_`, `client_ip`, `method`, CAST(`status_code` AS VARCHAR) AS status_code, FROM KafkaSource1;
Improper use of the CAST() data conversion function may result in accuracy loss, for example, from BIGINT to INTEGER or TINYINT. Please use it with caution.
<!-->For the type conversion between a string (VARCHAR) and a timestamp (TIMESTAMP), see functions such as TO_TIMESTAMP, DATE_FORMAT_SIMPLE and DATE_FORMAT in Time-related Functions.-->