Postgresql 中文操作指南
EXECUTE IMMEDIATE
EXECUTE IMMEDIATE — 动态准备并执行一条语句
EXECUTE IMMEDIATE — dynamically prepare and execute a statement
Description
EXECUTE IMMEDIATE 立即准备并执行一条动态指定的 SQL 语句，而不检索结果行。
EXECUTE IMMEDIATE immediately prepares and executes a dynamically specified SQL statement, without retrieving result rows.
Parameters
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string #
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A literal string or a host variable containing the SQL statement to be executed.
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Notes
在典型用法中， string 对一个包含动态构造的 SQL 语句的字符串的主机变量的引用。文本字符串的情况并不是很有用；你也可以直接编写 SQL 语句，而不需要使用 EXECUTE IMMEDIATE 进行额外的键入。
In typical usage, the string is a host variable reference to a string containing a dynamically-constructed SQL statement. The case of a literal string is not very useful; you might as well just write the SQL statement directly, without the extra typing of EXECUTE IMMEDIATE.
如果你确实使用文字字符串，请记住你可能希望包含在 SQL 语句中的任何双引号必须写成八进制转义字符 ( \042 )，而不是通常的 C 惯用法 \" 。这是因为字符串位于 EXEC SQL 部分中，因此 ECPG 词法分析器根据 SQL 规则而不是 C 规则对其进行解析。任何嵌入的反斜杠都会根据 C 规则得到处理；但 \" 会引起立即的语法错误，因为它被视为结束的文字。
If you do use a literal string, keep in mind that any double quotes you might wish to include in the SQL statement must be written as octal escapes (\042) not the usual C idiom \". This is because the string is inside an EXEC SQL section, so the ECPG lexer parses it according to SQL rules not C rules. Any embedded backslashes will later be handled according to C rules; but \" causes an immediate syntax error because it is seen as ending the literal.
Examples
下面是一个使用 EXECUTE IMMEDIATE 和名为 command 的主机变量执行 INSERT 语句的示例：
Here is an example that executes an INSERT statement using EXECUTE IMMEDIATE and a host variable named command:
sprintf(command, "INSERT INTO test (name, amount, letter) VALUES ('db: ''r1''', 1, 'f')");
EXEC SQL EXECUTE IMMEDIATE :command;