Adding more complete support for set operations: UNION / INTERSECT / …#84
Adding more complete support for set operations: UNION / INTERSECT / …#84javrucebo wants to merge 5 commits intohyrise:masterfrom
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…EXCEPT
Allow multiple operations, differentiate between the operators, honor parentheses
- internal data structure is changing. Instead of the `unionSelect` pointer
to a second SelectStatement two new vectors as members of
SelectStatement are introduced:
- setStatement: holds pointers to SelectStatement(s) right of first
set operation
- setType: holds pointers to new struct SetDescription with members
- type: Enum (kSetUnion, kSetIntersect, kSetExcept)
- all: bool to indicate if keyword ALL was used
- if no parentheses are used then there is only one set of vectors, e.g. for
SELECT a1 FROM t1 UNION SELECT a2 FROM t2 EXCEPT ALL SELECT a3 FROM t3
then setStatement holds two SelectStatements
SelectStatement
Table t1
ColumnRef a1
setStatement
SelectStatement
Table t2
ColumnRef a2
SelectStatement
Table t3
ColumnRef a3
setType
SetDescription
type kSetUnion
all false
SetDescription
type kSetExcept
all true
- if parentheses are used then nested structure is built e.g. for
SELECT a1 FROM t1 UNION (SELECT a2 FROM t2 EXCEPT ALL SELECT a3 FROM t3)
SelectStatement
Table t1
ColumnRef a1
setStatement
SelectStatement
Table t2
ColumnRef a2
setStatement
SelectStatement
Table t3
ColumnRef a3
setType
SetDescription
type kSetExcept
all true
setType
SetDescription
type kSetUnion
all false
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| SelectStatement* MakeOrAppendUnionList(SelectStatement* stmt, |
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It's not only a UnionList, is it? Maybe MakeOrAppendSetList?
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I have renamed to MakeOrAppendSetList as suggested
| TEST(SetOperations) { | ||
| SelectStatement* stmt; | ||
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| TEST_PARSE_SQL_QUERY("select a from t1 union select b from t2; \ |
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limit/order after set operations should probably included here? As in "SELECT a FROM t1 UNION (...) ORDER BY a LIMIT 5"
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I have added such tests for WHERE/LIMIT/ORDER as suggested
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The SELECT statement grammar could really use some doc or better names, but that's not your concern. The setType/setStatement architecture is a bit confusing (especially since "set" is such an ambiguous word) but I can see why you would use it. I guess if we increase the testing as requested this should be fine. |
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I agree the naming could be confusing. Happy to change if you have other suggestion. As you pointed out I chose naming as those are operations on sets. |
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Closing this issue since it is outdated. In the meantime, #138 already added additional set operations support. |
3 participants
Adding more complete support for set operations: UNION / INTERSECT / EXCEPT
Allow multiple operations, differentiate between the operators, honor parentheses
internal data structure is changing. Instead of the
unionSelectpointerto a second SelectStatement two new vectors as members of
SelectStatement are introduced:
setStatement: holds pointers to SelectStatement(s) right of first
set operation
setType: holds pointers to new struct SetDescription with members
if no parentheses are used then there is only one set of vectors, e.g. for
SELECT a1 FROM t1 UNION SELECT a2 FROM t2 EXCEPT ALL SELECT a3 FROM t3then setStatement holds two SelectStatements
SELECT a1 FROM t1 UNION (SELECT a2 FROM t2 EXCEPT ALL SELECT a3 FROM t3)