klausa PIVOT

Berlaku untuk: Databricks SQL Databricks Runtime

Mengubah baris table_reference sebelumnya dengan memutar nilai unik daftar kolom tertentu menjadi kolom terpisah.

Sintaks

PIVOT ( { aggregate_expression [ [ AS ] agg_column_alias ] } [, ...]
    FOR column_list IN ( expression_list ) )

column_list
 { column_name |
   ( column_name [, ...] ) }

expression_list
 { expression [ AS ] [ column_alias ] |
   { ( expression [, ...] ) [ AS ] [ column_alias] } [, ...] ) }

Parameter

• aggregate_expression

  Ekspresi jenis apa pun di mana semua referensi kolom table_reference adalah argumen untuk fungsi agregat.

• agg_column_alias

  Alias opsional untuk hasil agregasi. Jika tidak ada alias yang ditentukan, PIVOT menghasilkan alias berdasarkan aggregate_expression.

• column_list

  Kumpulan kolom yang akan diputar.

  • column_name

    Kolom dari table_reference.

• expression_list

  Memetakan nilai dari column_list ke kolom alias.

  • expression

    Ekspresi literal dengan tipe yang berbagi jenis umum terkecil dengan masing-masing column_name. Jika ekspresi bukan harfiah, Azure Databricks menaikkan NON_LITERAL_PIVOT_VALUES. Jika jenis tidak cocok, Azure Databricks menaikkan PIVOT_VALUE_DATA_TYPE_MISMATCH.

    Jumlah ekspresi di setiap tuple harus sesuai dengan jumlah column_names di column_list.

  • column_alias

    Alias opsional yang menentukan nama kolom yang dihasilkan. Jika tidak ada alias yang ditentukan, PIVOT menghasilkan alias berdasarkan expression.

Hasil

Tabel sementara dari formulir berikut:

• Semua kolom dari kumpulan hasil perantara dari table_reference yang belum ditentukan dalam aggregate_expression atau column_list.

  Kolom-kolom ini adalah kolom pengelompokan.

• Untuk setiap tuple expression dan kombinasi aggregate_expression, PIVOT menghasilkan satu kolom. Jenisnya adalah jenis dari aggregate_expression.

  Jika hanya ada satu aggregate_expression kolom diberi nama menggunakan column_alias. Jika tidak, itu bernama column_alias_agg_column_alias.

  Nilai dalam setiap sel adalah hasil dari aggregation_expression menggunakan FILTER ( WHERE column_list IN (expression, ...).

Kondisi kesalahan umum

• INCOMPARABLE_PIVOT_COLUMN
• NON_LITERAL_PIVOT_VALUES
• PIVOT_VALUE_DATA_TYPE_MISMATCH

Contoh

-- A very basic PIVOT
-- Given a table with sales by quarter, return a table that returns sales across quarters per year.
> CREATE TEMP VIEW sales(year, quarter, region, sales) AS
   VALUES (2018, 1, 'east', 100),
          (2018, 2, 'east',  20),
          (2018, 3, 'east',  40),
          (2018, 4, 'east',  40),
          (2019, 1, 'east', 120),
          (2019, 2, 'east', 110),
          (2019, 3, 'east',  80),
          (2019, 4, 'east',  60),
          (2018, 1, 'west', 105),
          (2018, 2, 'west',  25),
          (2018, 3, 'west',  45),
          (2018, 4, 'west',  45),
          (2019, 1, 'west', 125),
          (2019, 2, 'west', 115),
          (2019, 3, 'west',  85),
          (2019, 4, 'west',  65);

> SELECT year, region, q1, q2, q3, q4
  FROM sales
  PIVOT (sum(sales) AS sales
    FOR quarter
    IN (1 AS q1, 2 AS q2, 3 AS q3, 4 AS q4));
 year  region  q1   q2   q3  q4
 2018  east   100   20   40  40
 2019  east   120  110   80  60
 2018  west   105   25   45  45
 2019  west   125  115   85  65

-- The same query written without PIVOT
> SELECT year, region,
         sum(sales) FILTER(WHERE quarter = 1) AS q1,
         sum(sales) FILTER(WHERE quarter = 2) AS q2,
         sum(sales) FILTER(WHERE quarter = 3) AS q2,
         sum(sales) FILTER(WHERE quarter = 4) AS q4
  FROM sales
  GROUP BY year, region;
 year  region  q1   q2   q3  q4
 2018  east   100   20   40  40
 2019  east   120  110   80  60
 2018  west   105   25   45  45
 2019  west   125  115   85  65

-- Also PIVOT on region
> SELECT year, q1_east, q1_west, q2_east, q2_west, q3_east, q3_west, q4_east, q4_west
    FROM sales
    PIVOT (sum(sales) AS sales
      FOR (quarter, region)
      IN ((1, 'east') AS q1_east, (1, 'west') AS q1_west, (2, 'east') AS q2_east, (2, 'west') AS q2_west,
          (3, 'east') AS q3_east, (3, 'west') AS q3_west, (4, 'east') AS q4_east, (4, 'west') AS q4_west));
 year  q1_east  q1_west  q2_east  q2_west  q3_east  q3_west  q4_east  q4_west
 2018      100      105       20       25       40       45       40       45
 2019      120      125      110      115       80       85       60       65

-- The same query written without PIVOT
> SELECT year,
    sum(sales) FILTER(WHERE (quarter, region) IN ((1, 'east'))) AS q1_east,
    sum(sales) FILTER(WHERE (quarter, region) IN ((1, 'west'))) AS q1_west,
    sum(sales) FILTER(WHERE (quarter, region) IN ((2, 'east'))) AS q2_east,
    sum(sales) FILTER(WHERE (quarter, region) IN ((2, 'west'))) AS q2_west,
    sum(sales) FILTER(WHERE (quarter, region) IN ((3, 'east'))) AS q3_east,
    sum(sales) FILTER(WHERE (quarter, region) IN ((3, 'west'))) AS q3_west,
    sum(sales) FILTER(WHERE (quarter, region) IN ((4, 'east'))) AS q4_east,
    sum(sales) FILTER(WHERE (quarter, region) IN ((4, 'west'))) AS q4_west
    FROM sales
    GROUP BY year;
 year  q1_east  q1_west  q2_east  q2_west  q3_east  q3_west  q4_east  q4_west
 2018      100      105       20       25       40       45       40       45
 2019      120      125      110      115       80       85       60       65

-- To aggregate across regions the column must be removed from the input.
> SELECT year, q1, q2, q3, q4
  FROM (SELECT year, quarter, sales FROM sales) AS s
  PIVOT (sum(sales) AS sales
    FOR quarter
    IN (1 AS q1, 2 AS q2, 3 AS q3, 4 AS q4));
  year   q1   q2   q3   q4
  2018  205   45   85   85
  2019  245  225  165  125

-- The same query without PIVOT
> SELECT year,
    sum(sales) FILTER(WHERE quarter = 1) AS q1,
    sum(sales) FILTER(WHERE quarter = 2) AS q2,
    sum(sales) FILTER(WHERE quarter = 3) AS q3,
    sum(sales) FILTER(WHERE quarter = 4) AS q4
    FROM sales
    GROUP BY year;
  year   q1   q2   q3   q4
  2018  205   45   85   85
  2019  245  225  165  125

-- A PIVOT with multiple aggregations
> SELECT year, q1_total, q1_avg, q2_total, q2_avg, q3_total, q3_avg, q4_total, q4_avg
    FROM (SELECT year, quarter, sales FROM sales) AS s
    PIVOT (sum(sales) AS total, avg(sales) AS avg
      FOR quarter
      IN (1 AS q1, 2 AS q2, 3 AS q3, 4 AS q4));
 year  q1_total  q1_avg  q2_total  q2_avg  q3_total  q3_avg  q4_total  q4_avg
 2018       205  102.5         45   22.5         85   42.5         85   42.5
 2019       245  122.5        225  112.5        165   82.5        125   62.5

-- The same query without PIVOT
> SELECT year,
         sum(sales) FILTER(WHERE quarter = 1) AS q1_total,
         avg(sales) FILTER(WHERE quarter = 1) AS q1_avg,
         sum(sales) FILTER(WHERE quarter = 2) AS q2_total,
         avg(sales) FILTER(WHERE quarter = 2) AS q2_avg,
         sum(sales) FILTER(WHERE quarter = 3) AS q3_total,
         avg(sales) FILTER(WHERE quarter = 3) AS q3_avg,
         sum(sales) FILTER(WHERE quarter = 4) AS q4_total,
         avg(sales) FILTER(WHERE quarter = 4) AS q4_avg
    FROM sales
    GROUP BY year;
 year  q1_total  q1_avg  q2_total  q2_avg  q3_total  q3_avg  q4_total  q4_avg
 2018       205  102.5         45   22.5         85   42.5         85   42.5
 2019       245  122.5        225  112.5        165   82.5        125   62.5

-- Pivot values must be literals.
> SELECT * FROM sales
  PIVOT (sum(sales) FOR quarter IN (1 + 0 AS q1));
  Error: NON_LITERAL_PIVOT_VALUES

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