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How to cast and update a numeric value from string column only where applicable in MySQL?
You can use the CEIL() function from MySQL. Let us first create a table. Here, we have taken the first column as VARCHAR −
mysql> create table DemoTable -> ( -> Value varchar(20), -> UpdateValue int -> ); Query OK, 0 rows affected (1.08 sec)
Insert some records in the table using insert command −
mysql> insert into DemoTable(Value) values('100');
Query OK, 1 row affected (0.11 sec)
mysql> insert into DemoTable(Value) values('false');
Query OK, 1 row affected (0.10 sec)
mysql> insert into DemoTable(Value) values('true');
Query OK, 1 row affected (0.07 sec)
mysql> insert into DemoTable(Value) values('1');
Query OK, 1 row affected (0.07 sec)Display all records from the table using select statement −
mysql> select *from DemoTable;
This will produce the following output −
+-------+-------------+ | Value | UpdateValue | +-------+-------------+ | 100 | NULL | | false | NULL | | true | NULL | | 1 | NULL | +-------+-------------+ 4 rows in set (0.00 sec)
Following is the query to cast and update a numeric value from string column only where applicable −
mysql> update DemoTable -> set UpdateValue=ceil(cast(Value AS char(7))); Query OK, 4 rows affected (0.18 sec) Rows matched: 4 Changed: 4 Warnings: 0
Let us check the table records once again −
mysql> select *from DemoTable;
This will produce the following output −
+-------+-------------+ | Value | UpdateValue | +-------+-------------+ | 100 | 100 | | false | 0 | | true | 0 | | 1 | 1 | +-------+-------------+ 4 rows in set (0.00 sec)
Updated on: 12-Dec-2019
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