Usage of MySQL string connection functions

MySQL String concatenation function is a common function. The following describes the usage of MySQL String concatenation function in detail. I hope you can learn more about MySQL String concatenation function.

Usage:
CONCAT (str1, str2 ,...)

Returns the string generated by the connection parameter. If any parameter is NULL, the return value is NULL.

Note:
If all parameters are non-binary strings, the result is a non-binary string.
If the independent variable contains any binary string, the result is a binary string.
A numeric parameter is converted to an equivalent binary string format. To avoid this, you can use an explicit cast type, for example:
Select concat (CAST (int_col as char), char_col)

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 concat function of MySQL connects 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)  
 
 

Concat_ws function in MySQL
Usage:
CONCAT_WS (separator, str1, str2 ,...)

CONCAT_WS () represents CONCAT With Separator, which is a special form of CONCAT. The first parameter is the delimiter of other parameters. The separator is placed between the two strings to be connected. The delimiter can be a string or another parameter.
Note:
If the Delimiter is NULL, the result is NULL. The function ignores the NULL value after any separator parameter.

For example, separate the strings with commas (,).

 
 

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

Unlike the concat function in MySQL, The concat_ws function does not return NULL because of the NULL value during execution.

 
 

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

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