Query Types
| Type |
| SQL |
| RelAlg |
| a.k.a. |
| Scan |
| select * from R |
| R |
| - |
| Proj |
| select x,y from R |
| Proj[x,y]R |
| - |
| Sort |
| select * from R
order by x |
| Sort[x]R |
| ord |
| Sel1 |
| select * from R
where id = k |
| Sel[id=k]R |
| one |
| Seln |
| select * from R
where a = k |
| Sel[a=k]R |
| - |
| Join1 |
| select * from R,S
where R.id = S.r |
| R Join[id=r] S |
| - |
Different query classes exhibit different query processing behaviours.
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