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 
~/.sqliterc so they're always used.