Split SQL UPDATE and DELETE into separate documentation pages

Replaces the combined insert-update-delete.md with dedicated update.md
and delete.md pages for better navigation and discoverability. Enriches
both pages with verified behavior: response format, LIMIT not supported,
SET to NULL, and cross-references to existing docs.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: christophdb

docs/sql/delete.md

@@ -0,0 +1,46 @@
+---
+description: SeaTable SQL DELETE syntax — remove rows with WHERE conditions.
+---
+
+# DELETE
+
+Deletes one or more rows from a table. Works with both normal and Big Data storage.
+
+## Syntax
+
+```sql
+DELETE FROM tableName
+  [WHERE ...]
+```
+
+!!! warning "No WHERE = delete all rows"
+
+    If you omit the WHERE clause, **all rows** in the table will be deleted.
+
+`LIMIT` is not supported in `DELETE` statements.
+
+## Response
+
+`DELETE` returns `success: true` on success. The response does not include the number of deleted rows. If no rows match the WHERE condition, the response is still `success: true`.
+
+```json
+{
+  "success": true,
+  "metadata": null,
+  "results": null
+}
+```
+
+## Examples
+
+Delete rows matching a condition:
+
+```sql
+DELETE FROM Contacts WHERE Age<18
+```
+
+Delete rows with empty values:
+
+```sql
+DELETE FROM Contacts WHERE City IS NULL
+```

docs/sql/insert-update-delete.md

@@ -0,0 +1,59 @@
+---
+description: SeaTable SQL UPDATE syntax — modify rows with WHERE conditions and constant values.
+---
+
+# UPDATE
+
+Updates one or more rows in a table. Works with both normal and Big Data storage.
+
+## Syntax
+
+```sql
+UPDATE tableName
+  SET column1 = value [, column2 = value, ...]
+  [WHERE ...]
+```
+
+!!! warning "No WHERE = update all rows"
+
+    If you omit the WHERE clause, **all rows** in the table will be updated.
+
+The `value` in SET must be a **constant** (string, number, or boolean). Expressions and [functions](functions.md) are not supported in SET — see [not supported features](index.md#not-supported) for alternatives.
+
+The same column restrictions and multi-value rules as [INSERT](insert.md) apply. Not all column types can be written via SQL — see [column writability](limitations.md#column-writability) for details.
+
+`LIMIT` is not supported in `UPDATE` statements.
+
+## Setting values to NULL
+
+To clear a cell, set the column to `NULL`. Setting a text column to an empty string `""` also results in NULL — see [NULL values](limitations.md#null-values).
+
+```sql
+UPDATE Contacts SET City=NULL WHERE Name="Alice"
+```
+
+## Response
+
+`UPDATE` returns `success: true` on success. The response does not include the number of affected rows. If no rows match the WHERE condition, the response is still `success: true`.
+
+```json
+{
+  "success": true,
+  "metadata": null,
+  "results": null
+}
+```
+
+## Examples
+
+Update a single column:
+
+```sql
+UPDATE Contacts SET Adult=true WHERE Age>=18
+```
+
+Update multiple columns at once:
+
+```sql
+UPDATE Contacts SET Adult=true, `Age group`="18+" WHERE Age>=18
+```

docs/sql/update.md

@@ -232,7 +232,8 @@ nav:
       - sql/index.md
       - SELECT: sql/select.md
       - INSERT: sql/insert.md
-      - UPDATE, DELETE: sql/insert-update-delete.md
+      - UPDATE: sql/update.md
+      - DELETE: sql/delete.md
       - Limitations: sql/limitations.md
       - Functions: sql/functions.md
   - Plugin Development: