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SQL question brushing 584 Looking for user references

2022-07-01 16:45:00 【GRT should always work hard】

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Intuitively think of the following sql sentence 

# Write your MySQL query statement below
select name from customer where referee_id != 2

But the query result is wrong ,
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MySQL Use ternary logic —— TRUE, FALSE and UNKNOWN. Anything to do with NULL Values are compared with the third value UNKNOWN compare .

# Write your MySQL query statement below
select name from customer where referee_id != 2 or referee_id is null
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