WHERE 字段中,还可以有其他的连接条件,如在上例中,加上: INITCAP(s_dept.last_name) = ’Menchu’; 再如:WHERE s_emp.dept_id = s_dept.id AND s_dept.region_id = s_region.id AND s_emp.commission_pct > 0; 四、表别名ALIAS: 1、使用别名进行多表查询 。 2、仅在这个查询中生效,一旦用了...
//优先级:从低到高%nonassoc SET /* see relation_expr_opt_alias */%left UNION EXCEPT%left INTERSECT%left OR%left AND%right NOT%nonassoc IS ISNULL NOTNULL /* IS sets precedenceforIS NULL, etc */%nonassoc'<''>''='LESS_EQUALS GREATER_EQUALS NOT_EQUALS%nonassoc BETWEEN IN_P LIKE ILIK...
{SORTGROUPCLAUSE:tleSortGroupRef1:eqop96:sortop97:hashabletrue} ) } rewriter the query tree: ( {QUERY:commandType1:canSetTagtrue:hasAggstrue:rtable( {RANGETBLENTRY:eref{ALIAS:aliasnamefoo:colnames("a""b") }:rtekind0:relid16385:relkindr:rellockmode1:perminfoindex1:inhtrue:inFromCltrue...
* handling join alias Vars. Currently this is not needed because all join * alias Vars are expanded to non-aliased form during preprocess_expression. * 曾经,还制作了其他的树来表示连接rte,用于处理连接别名Vars。 * 目前不需要这样做,因为在preprocess_expression期间,所有连接别名Vars都被扩展为非别名形式。
:alias {ALIAS :aliasname*SELECT*\1:colnames<>} :eref {ALIAS :aliasname*SELECT*\1:colnames (""?column?"") } :rtekind1:subquery<>:security_barrier false :inh false :inFromCl false :requiredPerms0:checkAsUser0:selectedCols (b)
Table aliases can be used in WHERE, GROUP BY, HAVING, and ORDER BY clauses. When we need data from multiple tables, we need to join those tables by qualifying the columns using table name/table alias. The aliases are mandatory for inline queries (queries embedded within another sta...
$1->alias = alias; $$ = $1; } ; /* * TABLESAMPLE decoration in a FROM item */ tablesample_clause: TABLESAMPLE func_name '(' expr_list ')' opt_repeatable_clause { RangeTableSample *n = makeNode(RangeTableSample); /* n->relation will be filled in later */ n->method = $2; n...
joinaliasvars=0x0,functions=0x0,funcordinality=false,tablefunc=0x0,values_lists=0x0,ctename=0x0,ctelevelsup=0,self_reference=false,coltypes=0x0,coltypmods=0x0,colcollations=0x0,enrname=0x0,enrtuples=0,alias=0x1c4fd58,eref=0x1c72c98,lateral=false,inh=true,inFromCl=true,requiredPerms...
[ WITH [ RECURSIVE ] with_query [, ...] ] INSERT INTO table_name [ AS alias ] [ ( column_name [, ...] ) ] [ OVERRIDING { SYSTEM | USER } VALUE ] { DEFAULT VALUES | VALUES ( { expression | DEFAULT } [, ...] ) [, ...] | query } [ ON CONFLICT [ conflict_target ...
(list_length(subselect->jointree->fromlist)==1)result->rarg=(Node*)linitial(subselect->jointree->fromlist);elseresult->rarg=(Node*)subselect->jointree;result->usingClause=NIL;result->quals=whereClause;result->alias=NULL;result->rtindex=0;/* we don't need an RTE for it */returnresult...