> 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-statement.md).

# DECLARE STATEMENT

### DECLARE STATEMENT

DECLARE STATEMENT — 宣告 SQL 陳述式識別字

### 語法

```

EXEC SQL [ AT connection_name ] DECLARE statement_name STATEMENT
```

### 說明

`DECLARE STATEMENT` 宣告 SQL 陳述式識別字。SQL 陳述式識別字可與連線相關聯；動態 SQL 陳述式使用該識別字時，會使用相關聯的連線執行。宣告的命名空間是預編譯單元，不允許對同一 SQL 陳述式識別字進行多次宣告。請注意，若預編譯器以 Informix 相容模式執行且已宣告 SQL 陳述式，便不能將 `database` 用作游標名稱。

### 參數

*`connection_name`* [#](#ECPG-SQL-DECLARE-STATEMENT-CONNECTION-NAME) : 由 `CONNECT` 命令建立的資料庫連線名稱。

```
可省略 `AT` 子句，但這樣的陳述式沒有意義。
```

*`statement_name`* [#](#ECPG-SQL-DECLARE-STATEMENT-STATEMENT-NAME) : SQL 陳述式識別字名稱，可以是 SQL 識別字或主機變數。

### 注意事項

只有在宣告實際放在動態陳述式之前時，此關聯才有效。

### 範例

```

EXEC SQL CONNECT TO postgres AS con1;
EXEC SQL AT con1 DECLARE sql_stmt STATEMENT;
EXEC SQL DECLARE cursor_name CURSOR FOR sql_stmt;
EXEC SQL PREPARE sql_stmt FROM :dyn_string;
EXEC SQL OPEN cursor_name;
EXEC SQL FETCH cursor_name INTO :column1;
EXEC SQL CLOSE cursor_name;
```

### 相容性

`DECLARE STATEMENT` 是 SQL 標準的擴充功能，但可用於知名的資料庫管理系統。

### 另請參閱

[CONNECT](/client-interfaces/ecpg/ecpg-sql-commands/ecpg-sql-connect.md), [DECLARE](/client-interfaces/ecpg/ecpg-sql-commands/ecpg-sql-declare.md), [OPEN](/client-interfaces/ecpg/ecpg-sql-commands/ecpg-sql-open.md)

***

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


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