Files
lancedb/docs/src/sql.md
Tevin Wang b731a6aed9 Add docs code testing & documentation syntax changes (#196)
- Creates testing files `md_testing.py` and `md_testing.js` for testing
python and nodejs code in markdown files in the documentation
This listens for HTML tags as well: `<!--[language] code code
code...-->` will create a set-up file to create some mock tables or to
fulfill some assumptions in the documentation.
- Creates a github action workflow that triggers every push/pr to
`docs/**`
- Modifies documentation so tests run (mostly indentation, some small
syntax errors and some missing imports)

A list of excluded files that we need to take a closer look at later on:
```javascript
const excludedFiles = [
  "../src/fts.md",
  "../src/embedding.md",
  "../src/examples/serverless_lancedb_with_s3_and_lambda.md",
  "../src/examples/serverless_qa_bot_with_modal_and_langchain.md",
  "../src/examples/youtube_transcript_bot_with_nodejs.md",
];
```
Many of them can't be done because we need the OpenAI API key :(.
`fts.md` has some issues with the library, I believe this is still
experimental?

Closes #170

---------

Co-authored-by: Will Jones <willjones127@gmail.com>
2023-06-28 11:07:26 -07:00

121 lines
3.4 KiB
Markdown

# SQL filters
LanceDB embraces the utilization of standard SQL expressions as predicates for hybrid
filters. It can be used during hybrid vector search and deletion operations.
Currently, Lance supports a growing list of expressions.
* ``>``, ``>=``, ``<``, ``<=``, ``=``
* ``AND``, ``OR``, ``NOT``
* ``IS NULL``, ``IS NOT NULL``
* ``IS TRUE``, ``IS NOT TRUE``, ``IS FALSE``, ``IS NOT FALSE``
* ``IN``
* ``LIKE``, ``NOT LIKE``
* ``CAST``
* ``regexp_match(column, pattern)``
For example, the following filter string is acceptable:
<!-- Setup Code
```python
import lancedb
import numpy as np
uri = "data/sample-lancedb"
db = lancedb.connect(uri)
data = [{"vector": row, "item": f"item {i}"}
for i, row in enumerate(np.random.random((10_000, 2)).astype('int'))]
tbl = db.create_table("my_vectors", data=data)
```
-->
<!-- Setup Code
```javascript
const vectordb = require('vectordb')
const db = await vectordb.connect('data/sample-lancedb')
let data = []
for (let i = 0; i < 10_000; i++) {
data.push({vector: Array(1536).fill(i), id: `${i}`, content: "", longId: `${i}`},)
}
const tbl = await db.createTable('my_vectors', data)
```
-->
=== "Python"
```python
tbl.search([100, 102]) \
.where("""(
(label IN [10, 20])
AND
(note.email IS NOT NULL)
) OR NOT note.created
""")
```
=== "Javascript"
```javascript
tbl.search([100, 102])
.where(`(
(label IN [10, 20])
AND
(note.email IS NOT NULL)
) OR NOT note.created
`)
```
If your column name contains special characters or is a [SQL Keyword](https://docs.rs/sqlparser/latest/sqlparser/keywords/index.html),
you can use backtick (`` ` ``) to escape it. For nested fields, each segment of the
path must be wrapped in backticks.
=== "SQL"
```sql
`CUBE` = 10 AND `column name with space` IS NOT NULL
AND `nested with space`.`inner with space` < 2
```
!!! warning
Field names containing periods (``.``) are not supported.
Literals for dates, timestamps, and decimals can be written by writing the string
value after the type name. For example
=== "SQL"
```sql
date_col = date '2021-01-01'
and timestamp_col = timestamp '2021-01-01 00:00:00'
and decimal_col = decimal(8,3) '1.000'
```
For timestamp columns, the precision can be specified as a number in the type
parameter. Microsecond precision (6) is the default.
| SQL | Time unit |
|------------------|--------------|
| ``timestamp(0)`` | Seconds |
| ``timestamp(3)`` | Milliseconds |
| ``timestamp(6)`` | Microseconds |
| ``timestamp(9)`` | Nanoseconds |
LanceDB internally stores data in [Apache Arrow](https://arrow.apache.org/) format.
The mapping from SQL types to Arrow types is:
| SQL type | Arrow type |
|----------|------------|
| ``boolean`` | ``Boolean`` |
| ``tinyint`` / ``tinyint unsigned`` | ``Int8`` / ``UInt8`` |
| ``smallint`` / ``smallint unsigned`` | ``Int16`` / ``UInt16`` |
| ``int`` or ``integer`` / ``int unsigned`` or ``integer unsigned`` | ``Int32`` / ``UInt32`` |
| ``bigint`` / ``bigint unsigned`` | ``Int64`` / ``UInt64`` |
| ``float`` | ``Float32`` |
| ``double`` | ``Float64`` |
| ``decimal(precision, scale)`` | ``Decimal128`` |
| ``date`` | ``Date32`` |
| ``timestamp`` | ``Timestamp`` [^1] |
| ``string`` | ``Utf8`` |
| ``binary`` | ``Binary`` |
[^1]: See precision mapping in previous table.