@@ -89,6 +89,7 @@ SHARE return 'SHARE'
8989MODE return ' MODE'
9090OJ return ' OJ'
9191LIMIT return ' LIMIT'
92+ UNION return ' UNION'
9293
9394"," return ' ,'
9495"=" return ' ='
@@ -159,8 +160,32 @@ LIMIT return 'LIMIT'
159160%% /* language grammar*/
160161
161162main
162- : selectClauseEOF {return {nodeType: ' Main' : $1 };
163- | selectClause';' EOF {return {nodeType: ' Main' : $1 , hasSemicolon: true };
163+ : selectClause semicolonOptEOF {return {nodeType: ' Main' : $1 , hasSemicolon: $2 };
164+ | unionClause semicolonOptEOF {return {nodeType: ' Main' : $1 , hasSemicolon: $2 };
165+ ;
166+
167+ semicolonOpt
168+ : ';' {$$ = true
169+ | {$$ = false
170+ ;
171+
172+ unionClause
173+ : unionClauseNotParenthesized {$$ = $1
174+ | unionClauseParenthesized {$$ = $1
175+ ;
176+
177+ unionClauseParenthesized
178+ : selectClauseParenthesized UNION distinctOpt selectClauseParenthesized order_by_opt limit_opt {$$ = { type: ' Union' : $1 , distinctOpt: $3 , right: $4 , orderBy: $5 , limit: $6 };
179+ | selectClauseParenthesized UNION distinctOpt unionClauseParenthesized order_by_opt limit_opt {$$ = { type: ' Union' : $1 , distinctOpt: $3 , right: $4 , orderBy: $5 , limit: $6 }
180+ ;
181+
182+ selectClauseParenthesized
183+ : '(' selectClause')' {$$ = { type: ' SelectParenthesized' : $2 }
184+ ;
185+
186+ unionClauseNotParenthesized
187+ : selectClause UNION distinctOpt selectClause {$$ = { type: ' Union' : $1 , distinctOpt: $3 , right: $4 }
188+ | selectClause UNION distinctOpt unionClauseNotParenthesized {$$ = { type: ' Union' : $1 , distinctOpt: $3 , right: $4 }
164189 ;
165190
166191selectClause