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Tag: count

Counting number of joined rows in left join

I’m trying to write an aggregate query in SQL which returns the count of all records joined to a given record in a table; If no records were joined to the given record, then the result for that record should be 0: Data My database looks like this (I’m not able to change the structure, unfortunately): (MESSAGEPART has a composite

Fastest way to determine if record exists

As the title suggests… I’m trying to figure out the fastest way with the least overhead to determine if a record exists in a table or not. Sample query: Say the ? is swapped with ‘TB100’… both the first and second queries will return the exact same result (say… 1 for this conversation). The last query will return ‘TB100’ as

ILIKE and NOT ILIKE in aws redshift different from total

I ran three following queries in amazon redshift: The count was 1554. The count was 62. The count was 85. The last two (62 + 85) should equal 1554. What am I missing? Answer Double-quotes are for identifiers: “myColumn” Single quotes are for values: ‘value’. Your examples contradict those basic syntax rules. Also, you did not consider NULL values, which

H2 Get row count for all tables

I would like to know the total number of rows for each table. And that for all tables at once. Is this possible with H2? I’m thinking of a table: |table name | row size | At the moment I’m using the current version 1.3.170 (2012-11-30). Answer You would need to use a user-defined function, for example: This code doesn’t

MySQL: Count the distinct rows per day

I have an interesting query I need to do. I have a table with an INT column containing ip address numbers (using INET_ATON), and a timestamp column. I want to be able to count the number of unique ip address columns there are per day. That is, how many distinct ip rows there are in each day. So, for example,

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