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I have a table with two DATETIME columns.
One of them is never NULL, but one of them is sometimes NULL.
I need to write a query which will set all the NULL rows for column B equal to the values in column A.
I have tried this example but the SQL in the selected answer does not execute because MySQL Workbench doesn't seem to like the FROM in the UPDATE.
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UPDATE table SET col = new_value WHERE col = old_value AND other_col = some_other_value; UPDATE table SET col = new_value WHERE col = old_value OR other_col = some_other_value; As you can see, you can expand the WHERE clause as much as you'd like in order to filter down the rows for updating to what you need.
Update With Select Sub Query: Same Table. Thus, the simplest and straightforward way to update values from one table to another table is to use the UPDATE FROM SELECT statement. By using UPDATE FROM, you can avoid the complicated ways like cursors, table data type, temp table, etc.
Sounds like you're working in just one table so something like this:
update your_table set B = A where B is null If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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