语法格式

• 兼容PostgreSQL风格的创建自定义函数语法。

  CREATE [ OR REPLACE  ] FUNCTION function_name 
      ( [  { argname [ argmode  ] argtype [  { DEFAULT  | :=  | =  } expression  ]}  [, ...]  ] )
      [ RETURNS rettype [ DETERMINISTIC  ]  | RETURNS TABLE (  { column_name column_type  }  [, ...] )]
      LANGUAGE lang_name 
      [ 
         {IMMUTABLE  | STABLE  | VOLATILE }
          | {SHIPPABLE | NOT SHIPPABLE}
          | WINDOW
          | [ NOT  ] LEAKPROOF  
          | {CALLED ON NULL INPUT  | RETURNS NULL ON NULL INPUT | STRICT } 
          | {[ EXTERNAL  ] SECURITY INVOKER | [ EXTERNAL  ] SECURITY DEFINER | AUTHID DEFINER  | AUTHID CURRENT_USER} 
          | {fenced | not fenced}
          | {PACKAGE}
          | COST execution_cost
          | ROWS result_rows
          | SET configuration_parameter { {TO | =} value | FROM CURRENT }
       ][...]
      {
          AS 'definition'
          | AS 'obj_file', 'link_symbol'
      };

• 兼容A风格的创建自定义函数的语法。

  CREATE [ OR REPLACE  ] FUNCTION function_name 
      ( [  { argname [ argmode  ] argtype [  { DEFAULT | := | =  } expression  ] }  [, ...]  ] )
      RETURN rettype [ DETERMINISTIC  ]
      [ 
          {IMMUTABLE  | STABLE  | VOLATILE } 
          | {SHIPPABLE | NOT SHIPPABLE}
          | {PACKAGE}
          | {FENCED | NOT FENCED}
          | [ NOT  ] LEAKPROOF  
          | {CALLED ON NULL INPUT | RETURNS NULL ON NULL INPUT | STRICT } 
          | {[ EXTERNAL  ] SECURITY INVOKER  | [ EXTERNAL  ] SECURITY DEFINER | AUTHID DEFINER | AUTHID CURRENT_USER} 
          | COST execution_cost  
          | ROWS result_rows  
          | SET configuration_parameter { {TO | =} value  | FROM CURRENT }
          | LANGUAGE lang_name
      ][...] 
      { 
        IS  | AS
      } plsql_body
  /