> 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/client-interfaces/ecpg/ecpg-sql-commands/ecpg-sql-declare.md).

# DECLARE

### DECLARE

DECLARE — 定義游標

### 語法

```

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
```

### 說明

`DECLARE` 宣告游標，以走訪備妥陳述式的結果集。此命令與直接 SQL 命令 `DECLARE` 的語意稍有不同：後者會執行查詢並準備結果集以供擷取；此嵌入式 SQL 命令只會宣告一個名稱作為走訪查詢結果集的「迴圈變數」，實際執行會在以 `OPEN` 命令開啟游標時發生。

### 參數

*`cursor_name`* [#](#ECPG-SQL-DECLARE-CURSOR-NAME) : 游標名稱，區分大小寫。可以是 SQL 識別字或主機變數。

*`prepared_name`* [#](#ECPG-SQL-DECLARE-PREPARED-NAME) : 備妥查詢的名稱，可以是 SQL 識別字或主機變數。

*`query`* [#](#ECPG-SQL-DECLARE-QUERY) : 提供游標要傳回資料列的 [SELECT](/reference/sql-commands/sql-select.md) 或 [VALUES](/reference/sql-commands/sql-values.md) 命令。

游標選項的意義請參閱 [DECLARE](/reference/sql-commands/sql-declare.md)。

### 範例

以下範例為查詢宣告游標：

```

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();
```

以下範例為備妥陳述式宣告游標：

```

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

### 相容性

SQL 標準規定了 `DECLARE`。

### 另請參閱

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

***

原文：[PostgreSQL 18.6 Documentation](https://www.postgresql.org/docs/18/ecpg-sql-declare.html)（英文原文，待翻譯）


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