Postgresql 中文操作指南

44.3. Data Values in PL/Tcl #

提供给 PL/Tcl 函数代码的参数值只是转换为文本形式的输入参数（就像在 SELECT 语句中显示它们一样）。相反，return 和 return_next 命令将接受任何字符串，该字符串是函数声明结果类型的可接受输入格式，或者复合结果类型的指定列的输入格式。

The argument values supplied to a PL/Tcl function’s code are simply the input arguments converted to text form (just as if they had been displayed by a SELECT statement). Conversely, the return and return_next commands will accept any string that is acceptable input format for the function’s declared result type, or for the specified column of a composite result type.