Program:
// Lex file: sq.l
alpha [A-Za-z]
digit [0-9]
%%
[ \t\n]
select return SELECT;
distinct return DISTINCT;
from return FROM;
where return WHERE;
like return LIKE;
desc return DESC;
asc return ASC;
"group by" return GROUP;
having return HAVING;
"order by" return ORDER;
or return OR;
and return AND;
in return IN;
{digit}+ return NUM;
{alpha}({alpha}|{digit})* return ID;
"<=" return LE;
">=" return GE;
"==" return EQ;
"!=" return NE;
. return yytext[0];
%%
// Yacc file: sq.y
%{
#include <stdio.h>
#include <stdlib.h>
%}
%token ID NUM SELECT DISTINCT FROM WHERE LE GE EQ NE OR AND LIKE GROUP HAVING ORDER ASC DESC IN
%right '='
%left AND OR
%left '<' '>' LE GE EQ NE
%%
S : ST1';' {printf("INPUT ACCEPTED...\n");exit(0);};
ST1 : SELECT attributeList FROM tableList ST2
| SELECT DISTINCT attributeList FROM tableList ST2
;
ST2 : WHERE COND ST3
| ST3
;
ST3 : GROUP attributeList ST4
| ST4
;
ST4 : HAVING COND ST5
| ST5
;
ST5 : ORDER attributeList ST6
|
;
ST6 : DESC
| ASC
|
;
attributeList : ID','attributeList
| '*'
| ID
;
tableList : ID',' tableList
| ID
;
COND : COND OR COND
| COND AND COND
| E
| ID IN '(' ST1 ')'
;
E : F'=' F
| F '<' F
| F '>' F
| F LE F
| F GE F
| F EQ F
| F NE F
| F OR F
| F AND F
| F LIKE F
;
F : ID
| NUM
;
%%
#include"lex.yy.c"
#include<ctype.h>
main()
{
printf("Enter the query:");
yyparse();
}
Output:
nn@linuxmint ~ $ lex sq.l
nn@linuxmint ~ $ yacc sq.y
nn@linuxmint ~ $ gcc y.tab.c -ll -ly
nn@linuxmint ~ $ ./a.out
Enter the query:select model from product where manufacture in ( select manuid from manufactures where manufacture = keltron);
INPUT ACCEPTED...
nn@linuxmint ~ $
// Lex file: sq.l
alpha [A-Za-z]
digit [0-9]
%%
[ \t\n]
select return SELECT;
distinct return DISTINCT;
from return FROM;
where return WHERE;
like return LIKE;
desc return DESC;
asc return ASC;
"group by" return GROUP;
having return HAVING;
"order by" return ORDER;
or return OR;
and return AND;
in return IN;
{digit}+ return NUM;
{alpha}({alpha}|{digit})* return ID;
"<=" return LE;
">=" return GE;
"==" return EQ;
"!=" return NE;
. return yytext[0];
%%
// Yacc file: sq.y
%{
#include <stdio.h>
#include <stdlib.h>
%}
%token ID NUM SELECT DISTINCT FROM WHERE LE GE EQ NE OR AND LIKE GROUP HAVING ORDER ASC DESC IN
%right '='
%left AND OR
%left '<' '>' LE GE EQ NE
%%
S : ST1';' {printf("INPUT ACCEPTED...\n");exit(0);};
ST1 : SELECT attributeList FROM tableList ST2
| SELECT DISTINCT attributeList FROM tableList ST2
;
ST2 : WHERE COND ST3
| ST3
;
ST3 : GROUP attributeList ST4
| ST4
;
ST4 : HAVING COND ST5
| ST5
;
ST5 : ORDER attributeList ST6
|
;
ST6 : DESC
| ASC
|
;
attributeList : ID','attributeList
| '*'
| ID
;
tableList : ID',' tableList
| ID
;
COND : COND OR COND
| COND AND COND
| E
| ID IN '(' ST1 ')'
;
E : F'=' F
| F '<' F
| F '>' F
| F LE F
| F GE F
| F EQ F
| F NE F
| F OR F
| F AND F
| F LIKE F
;
F : ID
| NUM
;
%%
#include"lex.yy.c"
#include<ctype.h>
main()
{
printf("Enter the query:");
yyparse();
}
nn@linuxmint ~ $ lex sq.l
nn@linuxmint ~ $ yacc sq.y
nn@linuxmint ~ $ gcc y.tab.c -ll -ly
nn@linuxmint ~ $ ./a.out
Enter the query:select model from product where manufacture in ( select manuid from manufactures where manufacture = keltron);
INPUT ACCEPTED...
nn@linuxmint ~ $
