And _% difference in SQL and the like and =

staff tables: 

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 =和like

Difference: = match a precise value, like a match range

select * from staff where name = 'bob';

 

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 select * from staff where name like 'bob';

 

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_with%

Differences: _ matches any one character,% matches any more characters 

 select * from staff where name like '_lice';

 

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select * from staff where name like '%e';

 

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concat: splicing 

select id,name, concat( name,'是', job) from staff;