What
will be the results of the next two queries:

SELECT 'I like '+ NULL + 'SQL.'

SELECT CONCAT('I like ', NULL, 'SQL.') ?

Question

What
will be the results of the next two queries:

SELECT  'I like '+ NULL + 'SQL.'

SELECT  CONCAT('I like ', NULL, 'SQL.') ?

Answer

The first query returns NULL, the second returns
the  string ‘I like SQL.’

Answer

Both return the string ‘I like SQL.’

Answer

The first query failes, the second returns the  string ‘I like SQL.’

Answer

Both return NULL

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