oracle 非數字型轉數字型

   
oracle中如果一個字段內容不全是數字型 可以通過以下方式過濾 

to_number(substr(translate(a.vital_signs_cvalues,
                                  '9876543210.' || a.vital_signs_cvalues,
                                  '9876543210.'),
                        1,
                        instr(translate(a.vital_signs_cvalues,
                                        '9876543210.' ||
                                        a.vital_signs_cvalues,
                                        '9876543210.'),
                              '.')) || REPLACE(substr(translate(a.vital_signs_cvalues,
                                                                '9876543210.' ||
                                                                a.vital_signs_cvalues,
                                                                '9876543210.'),
                                                      instr(translate(a.vital_signs_cvalues,
                                                                      '9876543210.' ||
                                                                      a.vital_signs_cvalues,
                                                                      '9876543210.'),
                                                            '.') + 1,
                                                      length(translate(a.vital_signs_cvalues,
                                                                       '9876543210.' ||
                                                                       a.vital_signs_cvalues,
                                                                       '9876543210.'))),
                                               '.',
                                               '')) AS vital_signs_cvalues,