Query data code description

Limits

Dataphin returns a maximum of 10,000 query result records. You can append limit number of returns to a query statement to customize the number of returned records. For example, select * from ht5_out limit 20; retrieves 20 records.

Notes

• If a data query task runs for more than 2 hours, Dataphin automatically terminates the task to free up resources and keep other tasks running smoothly.

• Querying a logical aggregate table with the select * syntax can consume significant resources. We recommend that you avoid using select * in ad hoc queries on logical aggregate tables. For more information, see set the engine for ad hoc queries.

Code description for querying data

• Query logical table data.

SELECT * FROM sectionEnglishName.logicalTableName WHERE ds='${bizdate}';

Where:

• Module English Name: The Module English Name of the module to which the logical table belongs.

  You can find the module English name on the data section page.

  

  Note

  When querying data in a development environment, append _DEV to the Sectionenglishname, resulting in Sectionenglishname_dev.

• logicalTableName: The name of the logical table to be queried.

• ds='${bizdate}': The partition date for the query. The built-in Dataphin global variable ${bizdate} defaults to the format yyyyMMdd and represents the day before the current date. You can also specify an exact date, such as ds='20210223'.

• Query physical table data.

  SELECT * FROM projectEnglishName.physicalTableName WHERE ds='${bizdate}';

  Where:

  • Projectenglishname: The English name of the project that contains the physical table.

    You can find the project English name on the project information settings page.

  • Physicaltablename: The name of the physical table to be queried.

  • ds='${bizdate}': The partition date for the query. The built-in Dataphin global variable ${bizdate} defaults to the format yyyyMMdd and represents the day before the current date. You can also specify an exact date, such as ds='20210223'.