String
BigQuery
LEFT
BigQueryExtracts a specified number of characters from the left (beginning) of a string. A more readable shorthand than SUBSTR for extracting leading characters.
Tipe hasil:
STRINGDiperbarui: 13 Jun 2026Syntax
SQL
LEFT(value, length)Parameter
valueSTRINGwajib
The source string
lengthINT64wajib
The number of characters to extract from the left
Contoh Penggunaan
Extract a Prefix
SQL
1 SELECT LEFT('BigQuery', 3) as result;
Extracts the first 3 characters.
Hasil
Big
Country Code from Phone Number
SQL
1 SELECT 2 phone_number, 3 LEFT(phone_number, 3) as country_code 4 FROM `project.dataset.contacts` 5 WHERE phone_number LIKE '+1%' 6 LIMIT 3;
Extracts the country code from a phone number.
Hasil
| phone_number | country_code |
|---|---|
| +12025551234 | +1 |
| +14155552345 | +1 |
Masking Sensitive Data
SQL
1 SELECT 2 email, 3 CONCAT(LEFT(email, 3), '***@', SPLIT(email, '@')[OFFSET(1)]) as masked_email 4 FROM `project.dataset.users` 5 LIMIT 3;
Hides part of an email address for privacy.
Hasil
| masked_email | |
|---|---|
| john.doe@gmail.com | joh***@gmail.com |
| jane@company.com | jan***@company.com |
Categorize by Prefix
SQL
1 SELECT 2 LEFT(sku, 2) as category, 3 COUNT(*) as product_count 4 FROM `project.dataset.products` 5 GROUP BY category 6 ORDER BY product_count DESC;
Groups products by their SKU prefix.
Hasil
| category | product_count |
|---|---|
| EL | 450 |
| FA | 320 |
| FO | 280 |
Pertanyaan Umum tentang LEFT
Apa itu fungsi LEFT di BigQuery?
Extracts a specified number of characters from the left (beginning) of a string. A more readable shorthand than SUBSTR for extracting leading characters. Di BigQuery, fungsi LEFT termasuk dalam kelompok fungsi yang sering digunakan untuk mengolah dan menganalisis data secara efisien.
Bagaimana cara menggunakan LEFT di BigQuery?
Gunakan sintaks berikut: LEFT(value, length). Pastikan argumen yang dimasukkan sudah sesuai dengan tipe data yang diharapkan.
Apa nilai yang dikembalikan oleh fungsi LEFT?
Fungsi LEFT mengembalikan nilai bertipe STRING. 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 LEFT?
Fungsi ini memiliki 2 parameter wajib. Parameter yang digunakan: value (STRING, wajib): The source string; length (INT64, wajib): The number of characters to extract from the left.
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