sql - Can I alias multiple columns? How? -

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i'm using pyodbc , postgres.

can alias multiple columns?

here's description of problem:

data structure:

data id | c1  | c2 ------------- 1  | 11  | 12 2  | 21  | 22

notation: c column

dictionary id | key | value ---------------- 1  | k1  | v11 1  | k2  | v12 2  | k1  | v21 2  | k2  | v22

notation: k key, v value

you can think of k1 , k2 2 more columns. data structure way because it's changing. didn't design it, have go it.

i can't figure out sql query give me following (most importantly, row, can access k1 , k2 columns name):

data id | c1  | c2  | k1  | k2 ------------------------- 1  | 11  | 12  | v11 | v12 2  | 21  | 22  | v21 | v22

the problem keep running if alias tables, sql result contain 2 "key" columns dictionary table, meaning can't control column access of two, if alias rows, can't control tables being referenced inside sql statement.

the fix i'm thinking alias 2 columns:

select * data full join dictionary a1,a2,a3 on data.id = a1 full join dictionary a4,a5,a6 on data.id = a4 a2 = k1 , a5 = k2

notation: alias

the result of theoretically like

data id | c1  | c2  | a3  | a6  -------------------------  1  | 11  | 12  | v11 | v12 2  | 21  | 22  | v21 | v22

note a's technically here, 3 , 6 ones i'm interested in

you can alias entire table, example dictionary d1. refer column names in table d1.col1. example:

select  d.id ,       d.c1 ,       d.c2 ,       d1.value a3 ,       d2.value a6    data d left join         dictionary d1 on      data.id = d1.id         , d1.key = 'k1' left join         dictionary d2 on      data.id = d2.id         , d2.key = 'k2'

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