Performing Column Updates in MySQL
To modify a column in a table, it is crucial to utilize appropriate SQL commands. In this instance, altering the contents of a column without affecting other columns requires an update operation.
UPDATE vs. INSERT: Understanding the Difference
The scenario described involves altering the values of the col_a column. This cannot be accomplished using an INSERT statement, as it serves to insert new rows into a table. Instead, the UPDATE command should be employed, which enables modifications to existing data.
Using the UPDATE Command
The syntax of the UPDATE command is as follows:
UPDATE table_name SET column_name = new_value WHERE condition;
Specific Example: Updating 'col_a' Column
To update the col_a column specifically, the following commands can be used:
UPDATE table1 SET col_a='foo' WHERE key_col='k1'; UPDATE table1 SET col_a='bar' WHERE key_col='k2';
By utilizing these commands, the values of the col_a column for the rows with key_col values of 'k1' and 'k2' will be updated to 'foo' and 'bar', respectively.
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