Split The Column which is delimited into separate Rows in Teradata 14

问题

Can any one help me in solving this. In a table, I have the data like this right now.

How do i split the column Nodes which has delimiter TTBFA-TTBFB-TTBFC-TTBFD into 4 rows with other columns being same.

california region GAXAEB 102,520,000 18.71 4 8/30/2014

california region TTBFA 92,160,000 23.33 3 9/13/2014

california region TTBFB 92,160,000 23.33 3 9/13/2014

california region TTBFC 92,160,000 23.33 3 9/13/2014

california region TTBFD 92,160,000 23.33 3 9/13/2014

The value for column NODES is not always 5 characters , It may vary like below

Thanks in advance

回答1:

you could use (whatever number is your max number of nodes) UNION ALL statements and SUBSTRING with INSTR for the possible locations for a node

try something like:

        SELECT region_name, nodes AS node, 
               sgspeed, sgutil, portCount, WeekendingDate
        FROM t
        WHERE instr(nodes,'-') = 0
        UNION ALL
        SELECT region_name, SUBSTRING(nodes  FROM instr(nodes,'-',1,1) +1 FOR instr(nodes,'-',1,2)-1) AS node, 
               sgspeed, sgutil, portCount, WeekendingDate
        FROM t
        WHERE instr(nodes,'-') > 0
        UNION ALL
        SELECT region_name, SUBSTRING(nodes  FROM instr(nodes,'-',1,2) +1 FOR instr(nodes,'-',1,3)-1) AS node, 
               sgspeed, sgutil, portCount, WeekendingDate
        FROM t
        WHERE instr(nodes,'-',1,2) > 0
        UNION ALL
        SELECT region_name, SUBSTRING(nodes  FROM instr(nodes,'-',1,3) +1 FOR instr(nodes,'-',1,4)-1) AS node, 
               sgspeed, sgutil, portCount, WeekendingDate
        FROM t
        WHERE instr(nodes,'-',1,3) > 0
    ...

回答2:

The function INSTR usually implies you're running TD14+.

There's also the STRTOK function, better use this instead of SUBSTRING(INSTR).

And instead of up to 15 UNION ALLs you can also cross join to a table with numbers:

SELECT region_name, STRTOK(nodes, '-', i) AS x
FROM table
CROSS JOIN
 ( -- better don't use sys_calendar.CALENDAR as there are no statistics on day_of_calendar
   SELECT day_of_calendar AS i
   FROM sys_calendar.CALENDAR
   WHERE i <= 15
 ) AS dt
WHERE x IS NOT NULL

And you can utilize STRTOK_SPLIT_TO_TABLE in TD14, too:

SELECT * 
FROM table AS t1
JOIN 
(
   SELECT * 
   FROM TABLE (STRTOK_SPLIT_TO_TABLE(table.division, table.nodes, '-')
      RETURNS (division VARCHAR(30) CHARACTER SET UNICODE
              ,tokennum INTEGER
              ,token VARCHAR(30) CHARACTER SET UNICODE)
              ) AS dt
 ) AS t2
ON t1.division = t2.division

Hopefully this is for data cleansing and not for daily use...

回答3:

This is working fine.

select  
REGION_NAME,
case when POSITION('-' IN Nodes) = 0  then NODES else SUBSTRING(Nodes,0,POSITION('-' IN Nodes)) end as node, 
SgSpeed, 
SgUtil,
PortCount, 
WeekEndingDate 
FROM table

UNION 

select
REGION_NAME,
SUBSTRING(nodes  FROM instr(nodes,'-',1,1)+1 for instr(nodes,'-',1,1)-1) AS node, 
SgSpeed, 
SgUtil,
PortCount, 
WeekEndingDate
FROM table
WHERE instr(nodes,'-') > 0

UNION

select
REGION_NAME,
SUBSTRING(nodes  FROM instr(nodes,'-',1,2)+1 for instr(nodes,'-',1,1)-1) AS node, 
SgSpeed, 
SgUtil,
PortCount, 
WeekEndingDate
FROM table
WHERE instr(nodes,'-') > 0

UNION

select
REGION_NAME,
SUBSTRING(nodes  FROM instr(nodes,'-',1,3)+1 for instr(nodes,'-',1,1)-1) AS node, 
SgSpeed, 
SgUtil,
PortCount, 
WeekEndingDate 
FROM table
WHERE instr(nodes,'-') > 0

来源：https://stackoverflow.com/questions/27044188/split-the-column-which-is-delimited-into-separate-rows-in-teradata-14

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sql

teradata