How to check if a column exist in a MySQL table?
To understand whether a column exist or not, we have the following approaches −
- With the help of DESC command
- Using SHOW command
Firstly, we will create a table with columns −
mysql> CREATE table ColumnExistDemo
-> (
-> UniqueId int,
-> UniqueName varchar(200),
-> UniqueAddress varchar(200)
-> );
Query OK, 0 rows affected (0.57 sec)
In the first approach, we will get the entire column name with meaningful information. The syntax is as follows −
DESC yourTableName;
Let us apply the above query to check whether the column name exists or not. However, this approach is not good since it display all the columns.
mysql> DESC ColumnExistDemo;
The following is the output
+---------------+--------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+---------------+--------------+------+-----+---------+-------+
| UniqueId | int(11) | YES | | NULL | |
| UniqueName | varchar(200) | YES | | NULL | |
| UniqueAddress | varchar(200) | YES | | NULL | |
+---------------+--------------+------+-----+---------+-------+
3 rows in set (0.01 sec)
The second approach is better, since we can check for a single column. The syntax is as
follows −
SHOW COLUMNS from `yourTableName` LIKE 'yourColumnName';
Now, I am applying the above query to check whether colum exist or not. The query is as
follows −
mysql> SHOW COLUMNS from `ColumnExistDemo` LIKE 'UniqueName';
The following is the output
+------------+--------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+------------+--------------+------+-----+---------+-------+
| UniqueName | varchar(200) | YES | | NULL | |
+------------+--------------+------+-----+---------+-------+
1 row in set (0.00 sec)
Published on 22-Oct-2018 13:37:39
