[PGS9.2] Convert Data Type

/********************************************************************************************
-- Title : [PGS9.2] Convert Data Type
-- Reference : dbrang.tistory.com
-- Key word : data type 데이터 타입 형 변환 
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-- Can convert data type using "CONVERT()" or "{data}::TYPE"

create table ttt(a int, b varchar(10), c text);

insert into ttt values 

    (1, 'aaaaaaaaaa', 'aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa'),

    (2, 'bbbbbbbbbb', 'bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb'),

    (3, 'cccccccccc', 'cccccccccccccccccccccccccccccccccccccccccccccccccc');

   

select a, b::text || '  ' ||c "dd"

from ttt;

select cast(a as varchar(10)) || '  ' || b || '  ' || c

from ttt;

select a::varchar(10) || '  ' || b || '  ' || c

from ttt;

select a::text || '  ' || b::text || '  ' || c::text

from ttt;