Left Join in power query

Power Query
1

When we do Table A LEFT JOIN Table B, the no. of rows in Table A should remain unchanged, correct? Since we are just adding columns and not rows while performing join.
But is there any case in which the no. of rows in Table A will increase?

2

Hi @Anu,

Here’s a visual aid, illustrating join types.

image
image1597×991 171 KB

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or read a full article here

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3

I completely understand this, but my doubt is , Is there any case in which the no. of rows in Table A will increase?

4

Yes. If there are duplicate keys in Table B, then there will be multiple rows in the joined table. You will only get the exact same number of rows as are in Table A if there is only one (or none) matching record in Table B.
Greg

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5

if you are matching columns that have a duplicate in table B, you can end up with extra rows:

image

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