Window
BigQuery
LAG
BigQueryAccesses a value from a previous row in the partition based on the specified offset.
Tipe hasil:
Same as input expressionDiperbarui: 13 Jun 2026Syntax
SQL
LAG(expression [, offset [, default_value]]) OVER ([PARTITION BY partition_expression] ORDER BY sort_expression)Parameter
expressionanywajib
Column or expression whose value is retrieved
ORDER BYexpressionwajib
Determines the row ordering
offsetINT64opsional
Number of rows to look back (default: 1)
Default: 1
default_valuesame as expressionopsional
Value returned when no previous row exists
Contoh Penggunaan
Month-over-Month Comparison
SQL
1 SELECT 2 month, 3 revenue, 4 LAG(revenue) OVER (ORDER BY month) as prev_month_revenue, 5 revenue - LAG(revenue) OVER (ORDER BY month) as growth 6 FROM `project.dataset.monthly_sales`;
Calculates monthly growth by comparing revenue to the previous month.
Hasil
| month | revenue | prev_month | growth |
|---|---|---|---|
| 2024-01 | 100000 | NULL | NULL |
| 2024-02 | 120000 | 100000 | 20000 |
| 2024-03 | 115000 | 120000 | -5000 |
LAG with Default Value
SQL
1 SELECT 2 date, 3 stock_price, 4 LAG(stock_price, 1, stock_price) OVER (ORDER BY date) as prev_price 5 FROM `project.dataset.stocks`;
Uses the current price as the default value for the first row.
Pertanyaan Umum tentang LAG
Apa itu fungsi LAG di BigQuery?
Accesses a value from a previous row in the partition based on the specified offset. Di BigQuery, fungsi LAG termasuk dalam kelompok fungsi yang sering digunakan untuk mengolah dan menganalisis data secara efisien.
Bagaimana cara menggunakan LAG di BigQuery?
Gunakan sintaks berikut: LAG(expression [, offset [, default_value]]) OVER ([PARTITION BY partition_expression] ORDER BY sort_expression). Pastikan argumen yang dimasukkan sudah sesuai dengan tipe data yang diharapkan.
Apa nilai yang dikembalikan oleh fungsi LAG?
Fungsi LAG mengembalikan nilai bertipe Same as input expression. Pastikan tipe data hasil sudah sesuai dengan kebutuhan query atau formula kamu. Jika input mengandung nilai NULL, perilaku fungsi dapat berbeda — selalu periksa dokumentasi untuk memastikan hasilnya sesuai ekspektasi.
Apa saja parameter fungsi LAG?
Fungsi ini memiliki 2 parameter wajib dan 2 parameter opsional. Parameter yang digunakan: expression (any, wajib): Column or expression whose value is retrieved; offset (INT64, opsional): Number of rows to look back (default: 1); default_value (same as expression, opsional): Value returned when no previous row exists; ORDER BY (expression, wajib): Determines the row ordering.
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