On SQLite, I displayed the table "user" as shown below but "Null" is not displayed so I cannot differentiate between "Null" and Blank(Empty String):
sqlite> .header on
sqlite> .mode box
sqlite> select * from user;
┌────┬─────────────────┐
│ id │ name │
├────┼─────────────────┤
│ 1 │ Steve Jobs │
│ 2 │ │ <- Null
│ 3 │ │ <- Null
│ 4 │ Bill Gates │
│ 5 │ │ <- Blank(Empty String)
│ 6 │ Mark Zuckerberg │
└────┴─────────────────┘
Are there any ways to display "Null"?
This command below can set what to show for NULL
values:
.nullvalue <String>
So, set NULL
as shown below:
.nullvalue NULL
Then, NULL
is displayed for NULL
values as shown below:
sqlite> .headers on
sqlite> .mode box
sqlite> SELECT * FROM person;
┌────┬─────────────────┐
│ id │ name │
├────┼─────────────────┤
│ 1 │ Steve Jobs │
│ 2 │ NULL │ <- NULL
│ 3 │ NULL │ <- NULL
│ 4 │ Bill Gates │
│ 5 │ │ <- Blank(Empty String)
│ 6 │ Mark Zuckerberg │
└────┴─────────────────┘
Next, set This is NULL.
as shown below:
.nullvalue "This is NULL."
Then, This is NULL
is displayed for NULL
values as shown below:
sqlite> .headers on
sqlite> .mode box
sqlite> SELECT * FROM person;
┌────┬─────────────────┐
│ id │ name │
├────┼─────────────────┤
│ 1 │ Steve Jobs │
│ 2 │ This is NULL. │ <- NULL
│ 3 │ This is NULL. │ <- NULL
│ 4 │ Bill Gates │
│ 5 │ │ <- Blank(Empty String)
│ 6 │ Mark Zuckerberg │
└────┴─────────────────┘
And, these commands below can show the details of the command .nullvalue
:
.help .nullvalue
Or:
.help nullvalue
Then, this is how it looks like below:
sqlite> .help .nullvalue
.nullvalue STRING Use STRING in place of NULL values