Issues with a simple SQL Regex

Question

I have a Task to split the columns out of a SQL Statement. This worked well for me with a simple Java split on ",". But now i have an issue with additional commas inside the column. I guess the answer to this problem is pretty simple, but it will not get into my mind.

Example:

Source:

"Col_A BIGINT , COL_B TIMESTAMP , COL_C DECIMAL(10,30) , COL_D VARCHAR(20)"

My wanted Output:

Array[0] = Col_A BIGINT
Array[1] = COL_B TIMESTAMP
Array[2] = COL_C DECIMAL(10,30)
Array[3] = COL_D VARCHAR(20)

The real (and abvious) output:

Array[0] = Col_A BIGINT
Array[1] = COL_B TIMESTAMP
Array[2] = COL_C DECIMAL(10
Array[3] = 30)
Array[4] = COL_D VARCHAR(20)

The Obvious Problem is the comma between the two decimals (COL_C).

Now i am asking you if there is a nice solution on this Problem. I really want to use a single split to receive the different columns. But how can i avoid the wrong split at the decimal description.

I hope you guys can understand my problem. English is not my native language.

You have spaces around ,, split(" , "). Else, use split("\\s*,\\s*(?![^)]*\\))") (it is more a work around that will fail with some input later, best is to use matching approach). — Wiktor Stribiżew
– Wiktor Stribiżew, Commented Aug 5, 2016 at 7:38
Well the spaces were too obvious for me. My original statement is created by a DB2-Look. The spaces should be there every single time. I will give it a try, thanks for the reply — P Philipp
– P Philipp, Commented Aug 5, 2016 at 7:54

Shekhar Khairnar · Accepted Answer · 2016-08-05 13:57:16Z

1

You just split the given string with regex : ,(?!\d)

Find the , which is not followed by digit.

Code sample:

System.out.println(Arrays.toString("Col_A BIGINT , COL_B TIMESTAMP , COL_C DECIMAL(10,30) , COL_D VARCHAR(20)".split(",(?!\\d)")));

Demo and Explaination of regex

answered Aug 5, 2016 at 13:57

Shekhar Khairnar

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2 Comments

Wiktor Stribiżew Over a year ago

However, this still matches commas inside parentheses.

Shekhar Khairnar Over a year ago

Yes. But according to OP parantheses always having number that is size of column.

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