> For the complete documentation index, see [llms.txt](https://docs.postgresql.tw/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.postgresql.tw/15/client-interfaces/ecpg-embedded-sql-in-c/35.14.-embedded-sql-commands/ecpg-sql-declare.md).

# DECLARE

## DECLARE

DECLARE — define a cursor

### Synopsis

```

DECLARE cursor_name [ BINARY ] [ ASENSITIVE | INSENSITIVE ] [ [ NO ] SCROLL ] CURSOR [ { WITH | WITHOUT } HOLD ] FOR prepared_name
DECLARE cursor_name [ BINARY ] [ ASENSITIVE | INSENSITIVE ] [ [ NO ] SCROLL ] CURSOR [ { WITH | WITHOUT } HOLD ] FOR query
```

### Description

`DECLARE` declares a cursor for iterating over the result set of a prepared statement. This command has slightly different semantics from the direct SQL command `DECLARE`: Whereas the latter executes a query and prepares the result set for retrieval, this embedded SQL command merely declares a name as a “loop variable” for iterating over the result set of a query; the actual execution happens when the cursor is opened with the `OPEN` command.

### Parameters

*`cursor_name`*

A cursor name, case sensitive. This can be an SQL identifier or a host variable.

*`prepared_name`*

The name of a prepared query, either as an SQL identifier or a host variable.

*`query`*

A [SELECT](/15/reference/sql-commands/select.md) or [VALUES](/15/reference/sql-commands/values.md) command which will provide the rows to be returned by the cursor.

For the meaning of the cursor options, see [DECLARE](/15/reference/sql-commands/declare.md).

### Examples

Examples declaring a cursor for a query:

```

EXEC SQL DECLARE C CURSOR FOR SELECT * FROM My_Table;
EXEC SQL DECLARE C CURSOR FOR SELECT Item1 FROM T;
EXEC SQL DECLARE cur1 CURSOR FOR SELECT version();
```

An example declaring a cursor for a prepared statement:

```

EXEC SQL PREPARE stmt1 AS SELECT version();
EXEC SQL DECLARE cur1 CURSOR FOR stmt1;
```

### Compatibility

`DECLARE` is specified in the SQL standard.

### See Also

[OPEN](/15/client-interfaces/ecpg-embedded-sql-in-c/35.14.-embedded-sql-commands/ecpg-sql-open.md), [CLOSE](/15/reference/sql-commands/close.md), [DECLARE](/15/reference/sql-commands/declare.md)

***

原文：[PostgreSQL 15.19 Documentation](/15/client-interfaces/ecpg-embedded-sql-in-c/35.14.-embedded-sql-commands/ecpg-sql-declare.md)（英文原文，待翻譯）


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