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array_join
Description
Concatenates the elements of an array into a string.
Syntax
array_join(array, sep[, null_replace_str])
Parameters
array
: the array whose elements you want to concatenate. Only the ARRAY data type is supported.sep
: the delimiter that is used to separate the concatenated array elements. Only the VARCHAR data type is supported.null_replace_str
: the string that is used to substituteNULL
values. Only the VARCHAR data type is supported.
Return value
Returns a value of the VARCHAR data type.
Usage notes
The value of the
array
parameter must be a one-dimensional array.The
array
parameter does not support DECIMAL values.If you set the
sep
parameter toNULL
, the return value isNULL
.If you do not specify the
null_replace_str
parameter,NULL
values are discarded.If you set the
null_replace_str
parameter toNULL
, the return value isNULL
.
Examples
Example 1: Concatenate the elements of an array. In this example, the NULL
value in the array is discarded, and the concatenated array elements are separated by underscores (_
).
mysql> select array_join([1, 3, 5, null], '_');
+-------------------------------+
| array_join([1,3,5,NULL], '_') |
+-------------------------------+
| 1_3_5 |
+-------------------------------+
Example 2: Concatenate the elements of an array. In this example, the NULL
value in the array is substituted with NULL
strings, and the concatenated array elements are separated by underscores (_
).
mysql> select array_join([1, 3, 5, null], '_', 'NULL');
+---------------------------------------+
| array_join([1,3,5,NULL], '_', 'NULL') |
+---------------------------------------+
| 1_3_5_NULL |
+---------------------------------------+