diff options
Diffstat (limited to 'src/include/nodes/parsenodes.h')
| -rw-r--r-- | src/include/nodes/parsenodes.h | 70 |
1 files changed, 45 insertions, 25 deletions
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h index 3913d88ce91..6ac6d0be4da 100644 --- a/src/include/nodes/parsenodes.h +++ b/src/include/nodes/parsenodes.h @@ -7,7 +7,7 @@ * Portions Copyright (c) 1996-2000, PostgreSQL, Inc * Portions Copyright (c) 1994, Regents of the University of California * - * $Id: parsenodes.h,v 1.117 2000/10/18 16:16:10 momjian Exp $ + * $Id: parsenodes.h,v 1.118 2000/11/05 00:15:53 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -782,7 +782,7 @@ typedef struct InsertStmt /* * An INSERT statement has *either* VALUES or SELECT, never both. * If VALUES, a targetList is supplied (empty for DEFAULT VALUES). - * If SELECT, a complete SelectStmt (or SetOperation tree) is supplied. + * If SELECT, a complete SelectStmt (or set-operation tree) is supplied. */ List *targetList; /* the target list (of ResTarget) */ Node *selectStmt; /* the source SELECT */ @@ -816,51 +816,71 @@ typedef struct UpdateStmt /* ---------------------- * Select Statement + * + * A "simple" SELECT is represented in the output of gram.y by a single + * SelectStmt node. A SELECT construct containing set operators (UNION, + * INTERSECT, EXCEPT) is represented by a tree of SelectStmt nodes, in + * which the leaf nodes are component SELECTs and the internal nodes + * represent UNION, INTERSECT, or EXCEPT operators. Using the same node + * type for both leaf and internal nodes allows gram.y to stick ORDER BY, + * LIMIT, etc, clause values into a SELECT statement without worrying + * whether it is a simple or compound SELECT. * ---------------------- */ +typedef enum SetOperation +{ + SETOP_NONE = 0, + SETOP_UNION, + SETOP_INTERSECT, + SETOP_EXCEPT +} SetOperation; + typedef struct SelectStmt { NodeTag type; + /* + * These fields are used only in "leaf" SelectStmts. + */ List *distinctClause; /* NULL, list of DISTINCT ON exprs, or * lcons(NIL,NIL) for all (SELECT * DISTINCT) */ char *into; /* name of table (for select into table) */ + bool istemp; /* into is a temp table? */ List *targetList; /* the target list (of ResTarget) */ - List *fromClause; /* the from clause */ - Node *whereClause; /* qualifications */ + List *fromClause; /* the FROM clause */ + Node *whereClause; /* WHERE qualification */ List *groupClause; /* GROUP BY clauses */ - Node *havingClause; /* having conditional-expression */ + Node *havingClause; /* HAVING conditional-expression */ + /* + * These fields are used in both "leaf" SelectStmts and upper-level + * SelectStmts. portalname/binary may only be set at the top level. + */ List *sortClause; /* sort clause (a list of SortGroupBy's) */ char *portalname; /* the portal (cursor) to create */ bool binary; /* a binary (internal) portal? */ - bool istemp; /* into is a temp table */ Node *limitOffset; /* # of result tuples to skip */ Node *limitCount; /* # of result tuples to return */ List *forUpdate; /* FOR UPDATE clause */ + /* + * These fields are used only in upper-level SelectStmts. + */ + SetOperation op; /* type of set op */ + bool all; /* ALL specified? */ + struct SelectStmt *larg; /* left child */ + struct SelectStmt *rarg; /* right child */ + /* Eventually add fields for CORRESPONDING spec here */ } SelectStmt; /* ---------------------- - * Select Statement with Set Operations - * - * UNION/INTERSECT/EXCEPT operations are represented in the output of gram.y - * as a tree whose leaves are SelectStmts and internal nodes are - * SetOperationStmts. The statement-wide info (ORDER BY, etc clauses) - * is placed in the leftmost SelectStmt leaf. + * Set Operation node for post-analysis query trees * - * After parse analysis, there is a top-level Query node containing the leaf - * SELECTs as subqueries in its range table. Its setOperations field is the - * SetOperationStmt tree with leaf SelectStmt nodes replaced by RangeTblRef - * nodes. The statement-wide options such as ORDER BY are attached to this - * top-level Query. + * After parse analysis, a SELECT with set operations is represented by a + * top-level Query node containing the leaf SELECTs as subqueries in its + * range table. Its setOperations field shows the tree of set operations, + * with leaf SelectStmt nodes replaced by RangeTblRef nodes, and internal + * nodes replaced by SetOperationStmt nodes. * ---------------------- */ -typedef enum SetOperation -{ - SETOP_UNION, - SETOP_INTERSECT, - SETOP_EXCEPT -} SetOperation; - typedef struct SetOperationStmt { NodeTag type; @@ -870,7 +890,7 @@ typedef struct SetOperationStmt Node *rarg; /* right child */ /* Eventually add fields for CORRESPONDING spec here */ - /* This field is filled in during parse analysis: */ + /* Fields derived during parse analysis: */ List *colTypes; /* integer list of OIDs of output column types */ } SetOperationStmt; |