描述查詢

  • 發行項

適用于：核取標示為是 Databricks SQL 檢查標示為是 Databricks Runtime

傳回查詢輸出的中繼資料。

語法

{ DESC | DESCRIBE } [ QUERY ] input_statement

參數

  • 查詢

    這個子句是選擇性的，而且可以省略。

  • 查詢

    要描述的查詢。

例子

-- Create table `person`
> CREATE TABLE person (name STRING , age INT COMMENT 'Age column', address STRING);

-- Returns column metadata information for a simple select query
> DESCRIBE QUERY SELECT age, sum(age) FROM person GROUP BY age;
 col_name data_type    comment
 -------- --------- ----------
      age       int Age column
 sum(age)    bigint       null

-- Returns column metadata information for common table expression (`CTE`).
> DESCRIBE QUERY WITH all_names_cte
    AS (SELECT name FROM person) SELECT * FROM all_names_cte;
 col_name data_type comment
 -------- --------- -------
     name    string    null

-- Returns column metadata information for an inline table.
> DESCRIBE QUERY VALUES(100, 'John', 10000.20D) AS employee(id, name, salary);
 col_name data_type comment
 -------- --------- -------
       id       int    null
     name    string    null
   salary    double    null

-- Returns column metadata information for `TABLE` statement.
> DESCRIBE QUERY TABLE person;
 col_name data_type    comment
 -------- --------- ----------
     name    string       null
      age       int  Agecolumn
  address    string       null