Unit 7 · Data that lasts
SQL text values need single quotes
Without quotes, SQL reads Toronto as the name of a column and fails. Put text values in single quotes: WHERE city = 'Toronto'. Numbers need no quotes.
The mix-up
What people often think
“Text values can be typed as they are, like numbers.”
What the tutor says
Without quotes, SQL thinks Toronto is the name of a column. Put text in single quotes: 'Toronto'.
How it works
Use single quotes for text in SQL. Many databases read double quotes as names of columns or tables, not as text.
Side by side
The mix-upSQL
SELECT * FROM customers WHERE city = Toronto;What worksSQL
SELECT * FROM customers WHERE city = 'Toronto';Practise it with a tutor watching
Tables and rows
Read a database table and write SELECT, INSERT and a safe UPDATE in SQL.
20 minutes See it Build it Break it Say it
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