MySQL：如果是新的则插入或如果为NULL则更新

Question

我在MySQL中有这个表，如果行不存在我希望输入，否则只有在它们为NULL时才更新。

我知道mysql> mysql> describe patients; +------------------------------+--------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +------------------------------+--------------+------+-----+---------+----------------+ | patient_id | int(11) | NO | PRI | NULL | auto_increment | | patient_identifier | varchar(64) | NO | MUL | NULL | | | issuer_of_patient_identifier | int(11) | YES | MUL | NULL | | | medical_record_locator | varchar(64) | YES | | NULL | | | patient_name | varchar(128) | NO | MUL | NULL | | | birth_date | datetime | NO | | NULL | | | deceased_date | datetime | YES | | NULL | | | gender | varchar(16) | NO | | NULL | | | ethnicity | varchar(45) | YES | | NULL | | | date_created | datetime | NO | | NULL | | | last_update_date | datetime | YES | | NULL | | | last_updated_by | varchar(128) | NO | | NULL | | +------------------------------+--------------+------+-----+---------+----------------+ 12 rows in set (0.00 sec) 和MySQL是否有条件但无法弄清楚如何将它们放在一起。

mysql> select * from patients \G;
*************************** 1. row ***************************
                  patient_id: 4909
          patient_identifier: TG18-2002
issuer_of_patient_identifier: 11
      medical_record_locator: MRL 1
                patient_name: AAPM^Test^Patterns
                  birth_date: 1992-07-04 01:02:03
               deceased_date: NULL
                      gender: O
                   ethnicity: North American
                date_created: 2018-01-24 21:32:02
            last_update_date: 2018-01-24 21:32:02
             last_updated_by: indexStore
1 row in set (0.00 sec)

在评论中添加了Gordon要求的样本数据：

Updating multiple columns in one go:
mysql> update test1234 set col1=IF(col1 IS NULL OR col1 = ' ',70,col1), 
   col2=IF(col2 IS NULL OR col2 = ' ','abracadabra',col2) where col3=8;

示例MySQL如果条件为null则更新：

INSERT INTO JobsDB (Job_Name, Job_Desc, Job_Categ, Job_Qualif, Job_PayType, Job_Payrate, Job_PloyerName, Job_StartDate, Job_EndDate, Job_Status) 
VALUES ('" + tbName.Text + "' , '" + tbDescription.Text + "' , '" + ddCategory.Text + "' , '" + ddQualifications.Text + "' , '" + ddPayType.Text + "' , '" + tbRate.Text + "' , 'Kaslana' , '" + Convert.ToDateTime(calendarStart.SelectedDate) + "' , '" +Convert.ToDateTime(calendarEnd.SelectedDate) + "' , 'Active')

Answer 1

您可以使用IF子句中的ON DUPLICATE KEY。

示例：

INSERT INTO table (col1, col2)
VALUES (x, y)
ON DUPLICATE KEY UPDATE
col1 = IF(col1 IS NULL, VALUES(col1), col1),
col2 = IF(col2 IS NULL, VALUES(col2), col2);