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vtgate: expand qualified stars without JOIN USING coalescing #20759

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vtgate: expand qualified stars without JOIN USING coalescing #20759

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22 changes: 22 additions & 0 deletions go/vt/vtgate/planbuilder/testdata/select_cases.json
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Original file line number Diff line number Diff line change
Expand Up @@ -357,6 +357,28 @@
]
}
},
{
"comment": "qualified star after join using keeps the join column",
"query": "select b.* from authoritative a join authoritative b using (user_id)",
"plan": {
"Type": "Scatter",
"QueryType": "SELECT",
"Original": "select b.* from authoritative a join authoritative b using (user_id)",
"Instructions": {
"OperatorType": "Route",
"Variant": "Scatter",
"Keyspace": {
"Name": "user",
"Sharded": true
},
"FieldQuery": "select b.user_id, b.col1, b.col2 from authoritative as a, authoritative as b where 1 != 1",
"Query": "select b.user_id, b.col1, b.col2 from authoritative as a, authoritative as b where a.user_id = b.user_id"
},
"TablesUsed": [
"user.authoritative"
]
}
},
{
"comment": "select * from authoritative table",
"query": "select * from authoritative",
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5 changes: 5 additions & 0 deletions go/vt/vtgate/semantics/early_rewriter.go
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Original file line number Diff line number Diff line change
Expand Up @@ -1075,6 +1075,11 @@ func (r *earlyRewriter) expandTableColumns(
org: org,
expandedColumns: map[sqlparser.TableName][]*sqlparser.ColName{},
}
if !starExpr.TableName.IsEmpty() {
// USING coalescing applies to an unqualified * only: a qualified star
// returns every column of its table, join columns included
state.joinUsing = nil
}

for _, tbl := range tables {
if !starExpr.TableName.IsEmpty() && !tbl.matches(starExpr.TableName) {
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14 changes: 14 additions & 0 deletions go/vt/vtgate/semantics/early_rewriter_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -174,6 +174,20 @@ func TestExpandStar(t *testing.T) {
}, {
sql: "select 1 from t1 join t5 using (b) where b = 12",
expSQL: "select 1 from t1 join t5 on t1.b = t5.b where t1.b = 12",
}, {
// USING coalescing applies to an unqualified * only: a qualified star
// returns every column of its table, join columns included
sql: "select t2.* from t2 join t4 using (c1)",
expSQL: "select t2.c1, t2.c2 from t2 join t4 on t2.c1 = t4.c1",
}, {
sql: "select t4.* from t2 join t4 using (c1)",
expSQL: "select t4.c1, t4.c4 from t2 join t4 on t2.c1 = t4.c1",
}, {
sql: "select t2.*, t4.* from t2 join t4 using (c1)",
expSQL: "select t2.c1, t2.c2, t4.c1, t4.c4 from t2 join t4 on t2.c1 = t4.c1",
}, {
sql: "select t1.*, t5.* from t1 join t5 using (b)",
expSQL: "select t1.a, t1.b, t1.c, t5.a, t5.b from t1 join t5 on t1.b = t5.b",
}, {
sql: "select * from (select 12) as t",
expSQL: "select `12` from (select 12 from dual) as t",
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