String length and position functions in PostgreSQL - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to get the length of the string 'hello'.

PostgreSQL

SELECT [1]('hello');

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Alength

Bposition

Csubstr

Dchar_length

Attempts:

3 left

💡 Hint

Common Mistakes

Using position instead of length.

Using substr which extracts part of a string.

The length function returns the number of characters in a string in PostgreSQL.

2fill in blank

medium

Complete the code to find the position of 'a' in the string 'banana'.

PostgreSQL

SELECT [1]('a' IN 'banana');

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Astrpos

Blength

Cposition

Dchar_length

Attempts:

3 left

💡 Hint

Common Mistakes

Using length instead of position.

Using strpos which is similar but different syntax.

The position function returns the location of a substring inside a string in PostgreSQL.

3fill in blank

hard

Fix the error in the code to correctly find the position of 'na' in 'banana'.

PostgreSQL

SELECT position([1] IN 'banana');

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A'banana'

B'na'

C"na"

Dna

Attempts:

3 left

💡 Hint

Common Mistakes

Not using quotes around the substring.

Using double quotes which are for identifiers.

The substring must be a string literal enclosed in single quotes in PostgreSQL.

4fill in blank

hard

Fill both blanks to get the length of 'apple' and find the position of 'p' in it.

PostgreSQL

SELECT [1]('apple') AS len, [2]('p' IN 'apple') AS pos;

Drag options to blanks, or click blank then click option'

Alength

Bposition

Cchar_length

Dstrpos

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up length and char_length.

Using strpos instead of position.

length returns the string length, and position finds the substring position.

5fill in blank

hard

Fill all three blanks to create a query that returns a dictionary with the uppercase word as key, its length as value, and only include words where length is greater than 3.

PostgreSQL

SELECT jsonb_object_agg([1], [2]) FROM (SELECT UPPER(word) AS [1], [2] FROM words WHERE [3]) sub;

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Aword

Blength(word)

Clength(word) > 3

DUPPER(word)

Attempts:

3 left

💡 Hint

Common Mistakes

Using word instead of UPPER(word) for keys.

Not filtering words by length.

Using wrong syntax for filtering.

We use UPPER(word) as the key, length(word) as the value, and filter with length(word) > 3.