Where current not updating records
On the right-hand side, scroll down to get to the box that says, “Safe Updates”.
Through the ticking of this option, the software could prevent you from losing significant amounts of data or some of the changes you made earlier.
We can see that employee number 999901 is John Smith.
So, we can create a query with the following update statement: UPDATE “Employees”, SET, and then assign the value of the string “Stella” to the “first name” column, the string “Parkinson” to the “last name” column, the 31 of December 1990 to “birth date”, and “F” to “gender”.
You cannot restore data to a state corresponding to an earlier COMMIT.
In a nutshell, these are the SQL rules regarding transaction control.
If you don’t provide a WHERE condition, all rows of the table will be updated.
😊Assume we need the current version of this table for the rest of this tutorial. What we can infer from the lessons about the UPDATE statement is that you will rarely have to update an entire table.
Had we used a non-existent condition in the WHERE clause (for instance, an employee number of 999909), My SQL would have allowed the execution of the query, given that the SQL syntax is correct.
Nevertheless, nothing would have happened – the statement would have worked, affecting 0 rows, because the data table doesn’t contain an employee with such a number at the moment of the query’s execution.
So, let’s exit this connection and then reconnect, typing the password once again! In the previous post about SQL INSERT Statement, we inserted an employee under the number of 9-9-9-9-0-1, remember? The syntax to adhere to is UPDATE table name, the keyword SET, column names and the respective values assigned to them, and finally – WHERE, and a certain condition, or set of conditions, that must be satisfied.
Now, we are ready to dive into the UPDATE statement. By using this code structure, SQL will change the record or records satisfying the WHERE condition, updating the old values of the columns listed with the new ones.