1 | #pragma once |
2 | |
3 | #include <Parsers/IAST.h> |
4 | |
5 | |
6 | namespace DB |
7 | { |
8 | |
9 | /** List of zero, single or multiple JOIN-ed tables or subqueries in SELECT query, with ARRAY JOINs and SAMPLE, FINAL modifiers. |
10 | * |
11 | * Table expression is: |
12 | * [database_name.]table_name |
13 | * or |
14 | * table_function(params) |
15 | * or |
16 | * (subquery) |
17 | * |
18 | * Optionally with alias (correlation name): |
19 | * [AS] alias |
20 | * |
21 | * Table may contain FINAL and SAMPLE modifiers: |
22 | * FINAL |
23 | * SAMPLE 1 / 10 |
24 | * SAMPLE 0.1 |
25 | * SAMPLE 1000000 |
26 | * |
27 | * Table expressions may be combined with JOINs of following kinds: |
28 | * [GLOBAL] [ANY|ALL|ASOF|SEMI] [INNER|LEFT|RIGHT|FULL] [OUTER] JOIN table_expr |
29 | * CROSS JOIN |
30 | * , (comma) |
31 | * |
32 | * In all kinds except cross and comma, there are join condition in one of following forms: |
33 | * USING (a, b c) |
34 | * USING a, b, c |
35 | * ON expr... |
36 | * |
37 | * Also, tables may be ARRAY JOIN-ed with one or more arrays or nested columns: |
38 | * [LEFT|INNER|] ARRAY JOIN name [AS alias], ... |
39 | */ |
40 | |
41 | |
42 | /// Table expression, optionally with alias. |
43 | struct ASTTableExpression : public IAST |
44 | { |
45 | /// One of fields is non-nullptr. |
46 | ASTPtr database_and_table_name; |
47 | ASTPtr table_function; |
48 | ASTPtr subquery; |
49 | |
50 | /// Modifiers |
51 | bool final = false; |
52 | ASTPtr sample_size; |
53 | ASTPtr sample_offset; |
54 | |
55 | using IAST::IAST; |
56 | String getID(char) const override { return "TableExpression" ; } |
57 | ASTPtr clone() const override; |
58 | void formatImpl(const FormatSettings & settings, FormatState & state, FormatStateStacked frame) const override; |
59 | }; |
60 | |
61 | |
62 | /// How to JOIN another table. |
63 | struct ASTTableJoin : public IAST |
64 | { |
65 | /// Algorithm for distributed query processing. |
66 | enum class Locality |
67 | { |
68 | Unspecified, |
69 | Local, /// Perform JOIN, using only data available on same servers (co-located data). |
70 | Global /// Collect and merge data from remote servers, and broadcast it to each server. |
71 | }; |
72 | |
73 | /// Allows more optimal JOIN for typical cases. |
74 | enum class Strictness |
75 | { |
76 | Unspecified, |
77 | RightAny, /// Old ANY JOIN. If there are many suitable rows in right table, use any from them to join. |
78 | Any, /// Semi Join with any value from filtering table. For LEFT JOIN with Any and RightAny are the same. |
79 | All, /// If there are many suitable rows to join, use all of them and replicate rows of "left" table (usual semantic of JOIN). |
80 | Asof, /// For the last JOIN column, pick the latest value |
81 | Semi, /// LEFT or RIGHT. SEMI LEFT JOIN filters left table by values exists in right table. SEMI RIGHT - otherwise. |
82 | Anti, /// LEFT or RIGHT. Same as SEMI JOIN but filter values that are NOT exists in other table. |
83 | }; |
84 | |
85 | /// Join method. |
86 | enum class Kind |
87 | { |
88 | Inner, /// Leave only rows that was JOINed. |
89 | Left, /// If in "right" table there is no corresponding rows, use default values instead. |
90 | Right, |
91 | Full, |
92 | Cross, /// Direct product. Strictness and condition doesn't matter. |
93 | Comma /// Same as direct product. Intended to be converted to INNER JOIN with conditions from WHERE. |
94 | }; |
95 | |
96 | Locality locality = Locality::Unspecified; |
97 | Strictness strictness = Strictness::Unspecified; |
98 | Kind kind = Kind::Inner; |
99 | |
100 | /// Condition. One of fields is non-nullptr. |
101 | ASTPtr using_expression_list; |
102 | ASTPtr on_expression; |
103 | |
104 | using IAST::IAST; |
105 | String getID(char) const override { return "TableJoin" ; } |
106 | ASTPtr clone() const override; |
107 | |
108 | void formatImplBeforeTable(const FormatSettings & settings, FormatState & state, FormatStateStacked frame) const; |
109 | void formatImplAfterTable(const FormatSettings & settings, FormatState & state, FormatStateStacked frame) const; |
110 | void formatImpl(const FormatSettings & settings, FormatState & state, FormatStateStacked frame) const override; |
111 | }; |
112 | |
113 | inline bool isLeft(ASTTableJoin::Kind kind) { return kind == ASTTableJoin::Kind::Left; } |
114 | inline bool isRight(ASTTableJoin::Kind kind) { return kind == ASTTableJoin::Kind::Right; } |
115 | inline bool isInner(ASTTableJoin::Kind kind) { return kind == ASTTableJoin::Kind::Inner; } |
116 | inline bool isFull(ASTTableJoin::Kind kind) { return kind == ASTTableJoin::Kind::Full; } |
117 | inline bool isCross(ASTTableJoin::Kind kind) { return kind == ASTTableJoin::Kind::Cross; } |
118 | inline bool isComma(ASTTableJoin::Kind kind) { return kind == ASTTableJoin::Kind::Comma; } |
119 | inline bool isRightOrFull(ASTTableJoin::Kind kind) { return kind == ASTTableJoin::Kind::Right || kind == ASTTableJoin::Kind::Full; } |
120 | inline bool isLeftOrFull(ASTTableJoin::Kind kind) { return kind == ASTTableJoin::Kind::Left || kind == ASTTableJoin::Kind::Full; } |
121 | inline bool isInnerOrRight(ASTTableJoin::Kind kind) { return kind == ASTTableJoin::Kind::Inner || kind == ASTTableJoin::Kind::Right; } |
122 | |
123 | |
124 | /// Specification of ARRAY JOIN. |
125 | struct ASTArrayJoin : public IAST |
126 | { |
127 | enum class Kind |
128 | { |
129 | Inner, /// If array is empty, row will not present (default). |
130 | Left, /// If array is empty, leave row with default values instead of array elements. |
131 | }; |
132 | |
133 | Kind kind = Kind::Inner; |
134 | |
135 | /// List of array or nested names to JOIN, possible with aliases. |
136 | ASTPtr expression_list; |
137 | |
138 | using IAST::IAST; |
139 | String getID(char) const override { return "ArrayJoin" ; } |
140 | ASTPtr clone() const override; |
141 | void formatImpl(const FormatSettings & settings, FormatState & state, FormatStateStacked frame) const override; |
142 | }; |
143 | |
144 | |
145 | /// Element of list. |
146 | struct ASTTablesInSelectQueryElement : public IAST |
147 | { |
148 | /** For first element of list, either table_expression or array_join element could be non-nullptr. |
149 | * For former elements, either table_join and table_expression are both non-nullptr, or array_join is non-nullptr. |
150 | */ |
151 | ASTPtr table_join; /// How to JOIN a table, if table_expression is non-nullptr. |
152 | ASTPtr table_expression; /// Table. |
153 | ASTPtr array_join; /// Arrays to JOIN. |
154 | |
155 | using IAST::IAST; |
156 | String getID(char) const override { return "TablesInSelectQueryElement" ; } |
157 | ASTPtr clone() const override; |
158 | void formatImpl(const FormatSettings & settings, FormatState & state, FormatStateStacked frame) const override; |
159 | }; |
160 | |
161 | |
162 | /// The list. Elements are in 'children' field. |
163 | struct ASTTablesInSelectQuery : public IAST |
164 | { |
165 | using IAST::IAST; |
166 | String getID(char) const override { return "TablesInSelectQuery" ; } |
167 | ASTPtr clone() const override; |
168 | void formatImpl(const FormatSettings & settings, FormatState & state, FormatStateStacked frame) const override; |
169 | }; |
170 | |
171 | } |
172 | |