General SQL Parser can be use to remove duplicated parenthesis in SQL statement. After parsing sql query, all detailed parse tree information was available for further processing.<\/p>\n
Take this sql for example:<\/p>\n
\r\nselect * from ((select f from t1) union ((select f from t2)))\r\n<\/pre>\nyou can easily remove duplicated parenthesis in this subquery<\/p>\n
\r\n((select f from t2))\r\n<\/pre>\nwith code like this:<\/p>\n
\r\n private static int removeDuplicatedParenthesis(TSourceTokenList sourceTokenList){\r\n int cnt = 0;\r\n TSourceToken st = null, prevEndToken = null;\r\n boolean inParenthesis = false;\r\n for(int i=0;i<sourceTokenList.size();i++){\r\n st = sourceTokenList.get(i);\r\n if (st.isnonsolidtoken()) continue;\r\n if ((st.tokencode == '(')&&(st.getLinkToken() != null)){\r\n if (inParenthesis){\r\n if (st.getLinkToken() == prevEndToken.prevSolidToken()){\r\n \/\/this is duplicated token, remove this token\r\n st.setString(\"\");\r\n st.getLinkToken().setString(\"\");\r\n cnt++;\r\n }\r\n prevEndToken = st.getLinkToken();\r\n }else {\r\n inParenthesis = true;\r\n prevEndToken = st.getLinkToken();\r\n }\r\n }else {\r\n inParenthesis = false;\r\n prevEndToken = null;\r\n }\r\n }\r\n return cnt;\r\n }\r\n\r\n<\/pre>\nand the result sql will be like this:<\/p>\n
\r\nselect * from ((select f from t1) union (select f from t2))\r\n<\/pre>\nFor predicate in where clause, the same rule applied.<\/p>\n
\r\nselect * from user_table where ((username like '%admin%'));\r\n<\/pre>\nwill be turned into this one:<\/p>\n
\r\nselect * from user_table where (username like '%admin%');\r\n<\/pre>\nFor SQL like this:<\/p>\n
\r\nselect * from user_table where (f1 > 1 or f2 > 2) and f3 > 3;\r\n<\/pre>\nthis tool will not remove parenthesis which will change semantic of the original sql.<\/p>\n