当模式匹配段落时,awk /sed 提取信息

当模式匹配段落时,awk /sed 提取信息

我想在以 CREATE VIEW 开头并以“;”结尾的段落中搜索模式“FROM”并将结果保存在 csv 文件中。例如,如果我有以下文件:

CREATE VIEW view1
AS something  
FROM table1 ,table2 as A, table3 (something FROM table4)  
FROM table5, table6
USING file1
;
CREATE VIEW view2 
FROM table1 ,table2 ,table6 ,table4
something 
something 
FROM table5 ,table7 (something FROM table4 ,table5(this is something FROM table8)
USING file2
;

我希望得到以下结果:

view1;table1
view1;table2
view1;table3
view1;table4
view1;table5
view1;table6
view2;table1
view2;table2
view2;table6
view2;table4
view2;table5
view2;table7
view2;table4
view2;table5
view2;table8

答案1

编辑:忘记了第一行(所以我将 L++ 更改为 ++L):Edit2:修复了正则表达式,使其在最后一个 FROM 之前不会“通配”整个括号

我们也许能够“创造性地”使用字段分隔来删除我们不想保留的内容并只检索表名:

$ LC_ALL="C" awk -v csvsep=';' -v separators='FROM *| *, *| +as[^,]*| *[(][^()]*FROM *| *[)] *'  '
   /CREATE VIEW/ { name=$NF }
   /FROM / { nb=split($0,tables,separators);
             for(i=1;i<=nb;i++) {
               (tables[i]~/[A-Za-z]/) ? line[++L]=name csvsep tables[i] : rem="Otherwise nothing to add" }
           }
   END  { for(i=1;i<=L;i++) { print line[i] } }'

然后我们喂它:

CREATE VIEW view1
AS something
FROM table1 ,table2 as A, table3 (something FROM table4)
FROM table5, table6
USING file1
;
CREATE VIEW view2
FROM table1 ,table2 ,table6 ,table4
something
something
FROM table5 ,table7 (something FROM table4 ,table5(this is something FROM table8)
USING file2
;

它给出了预期的结果:

view1;table1
view1;table2
view1;table3
view1;table4
view1;table5
view1;table6
view2;table1
view2;table2
view2;table6
view2;table4
view2;table5
view2;table7
view2;table4
view2;table5
view2;table8

注意:我们只处理包含“FROM”的行,因此如果您有创意的 FROM 行(在多行上......),如果没有更多的魔法,它就无法工作。

答案2

TXR解决方案:

@(define word (w))@{w /[^,\s()]+/}@(end)
@(collect)
@  (cases)
CREATE VIEW @view@/ /
@  (or)
CREATE VIEW @view
@  (end)
@  (collect)
@    (coll :vars (table))@\
       FROM @(word first-tbl)@\
       @(coll :vars (rest-tbl) :gap 0)@\
         @/\s*,\s*/@(word rest-tbl)@\
         @(maybe) as @(word something)@(end)@\
       @(end)@\
       @(merge table first-tbl rest-tbl)@\
     @(end)
@  (until)
CREATE@(skip)
@  (end)
@  (flatten table)
@(end)
@(output)
@  (repeat)
@    (repeat)
@view;@table
@    (end)
@  (end)
@(end)

跑步:

$ txr 提取.txr 数据
视图1;表1
视图1;表2
视图1;表3
视图1;表4
视图1;表5
视图1;表6
视图2;表1
视图2;表2
视图2;表6
视图2;表4
视图2;表5
视图2;表7
视图2;表4
视图2;表5
视图2;表8

请注意,如果as出现为AS,则必须将其写入代码中;例如使用@/[Aa][Ss]/.

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