MySQL string processing function -- concat () function

MySQL string processing function concat () is used to connect one or more strings. It is one of the most important MySQL string processing functions. The following describes how to use this MySQL string processing function in detail.

The concat function of MySQL can connect one or more strings, such

 
 

  
  
mysql> select concat('10');  
  
  
+--------------+  
  
  
| concat('10') |  
  
  
+--------------+  
  
  
| 10   |  
  
  
+--------------+  
  
  
1 row in set (0.00 sec)  
  
  
 
  
  
mysql> select concat('11','22','33');  
  
  
+------------------------+  
  
  
| concat('11','22','33') |  
  
  
+------------------------+  
  
  
| 112233 |  
  
  
+------------------------+  
  
  
 
  
  
1 row in set (0.00 sec)  
 
 

When the MySQL concat MySQL string processing function is connected to a string, if one of them is NULL, NULL is returned.

 
 

  
  
mysql> select concat('11','22',null);  
  
  
+------------------------+  
  
  
| concat('11','22',null) |  
  
  
+------------------------+  
  
  
| NULL   |  
  
  
+------------------------+  
  
  
1 row in set (0.00 sec)  
 
 

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