在函数内执行带字符串的查询

Question

我必须在函数中执行以下查询：

SELECT year FROM tbl_people WHERE personal_card = 'A5B123';

返回一个整数。

问题是，我必须做以下事情：

EXECUTE 'SELECT year FROM tbl_people WHERE personal_card = 'A5B123'';

但是它将查询截断为：

SELECT year FROM tbl_people WHERE personal_card

我试过了：

EXECUTE "SELECT year FROM tbl_people WHERE personal_card = 'A5B123'";

但也失败了。

我怎样才能实现它？

Answer 1

SQL中的单引号are escaped by doubling them：

EXECUTE 'SELECT year FROM tbl_people WHERE personal_card = ''A5B123''';

但是在Postgres中更方便的方法是使用dollar quoted strings：

EXECUTE $$SELECT year FROM tbl_people WHERE personal_card = 'A5B123'$$;

Answer 2

您可以使用quote_literal这样的功能：

EXECUTE 'SELECT year FROM tbl_people WHERE personal_card = ' || quote_literal('A5B123');