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I have two tables with millions of records. Every so often I need to join them and exclude just a handful of records where a bit(1) column is set to 1 instead of 0. I can do it with either, WHERE ...
#5: Post edited
- I have two tables with millions of records. Every so often I need to join them and exclude just a handful of records where a bit(1) column is set to 1 instead of 0.
- I can do it with either,
- ```sql
- WHERE is_excluded !=1
- ```
- or
- ```sql
- WHERE example_table.pk NOT IN
- (
- SELECT pk FROM(
- SELECT pk FROM
- example_table
- WHERE is_excluded =1)
- AS t)
- ```
- For example
- ```
- UPDATE example_table
- SET textfield = 'X'
- WHERE textfield = 'Y'
- and pk not in (SELECT pk FROM (SELECT pk FROM example_table WHERE do_not_touch =1)as t) ;
- ```
- is faster than
- ```
- UPDATE example_table
- SET textfield = 'X'
- WHERE textfield = 'Y'
- and do_not_touch !=1
- ```
- The second way is sometimes way faster, even though it takes much longer to write out.
- Why would the second way be faster?
- I have two tables with millions of records. Every so often I need to join them and exclude just a handful of records where a bit(1) column is set to 1 instead of 0.
- I can do it with either,
- ```sql
- WHERE is_excluded !=1
- ```
- or
- ```sql
- WHERE example_table.pk NOT IN
- (
- SELECT pk FROM(
- SELECT pk FROM
- example_table
- WHERE is_excluded =1)
- AS t)
- ```
- For example
- ```
- UPDATE example_table
- SET textfield = 'X'
- WHERE textfield = 'Y'
- and pk not in (SELECT pk FROM (SELECT pk FROM example_table WHERE do_not_touch =1)as t) ;
- ```
- is faster than
- ```
- UPDATE example_table
- SET textfield = 'X'
- WHERE textfield = 'Y'
- and do_not_touch !=1
- ```
- The second way is sometimes way faster, even though it takes much longer to write out.
- Why would the second way be faster?
#4: Post edited
- I have two tables with millions of records. Every so often I need to join them and exclude just a handful of records where a bit(1) column is set to 1 instead of 0.
- I can do it with either,
- ```sql
- WHERE is_excluded !=1
- ```
- or
- ```sql
- WHERE example_table.pk NOT IN
- (
- SELECT pk FROM(
- SELECT pk FROM
- example_table
- WHERE is_excluded =1)
- AS t)
- ```
- The second way is sometimes way faster, even though it takes much longer to write out.
- Why would the second way be faster?
- I have two tables with millions of records. Every so often I need to join them and exclude just a handful of records where a bit(1) column is set to 1 instead of 0.
- I can do it with either,
- ```sql
- WHERE is_excluded !=1
- ```
- or
- ```sql
- WHERE example_table.pk NOT IN
- (
- SELECT pk FROM(
- SELECT pk FROM
- example_table
- WHERE is_excluded =1)
- AS t)
- ```
- For example
- ```
- UPDATE example_table
- SET textfield = 'X'
- WHERE textfield = 'Y'
- and pk not in (SELECT pk FROM (SELECT pk FROM example_table WHERE do_not_touch =1)as t) ;
- ```
- is faster than
- ```
- UPDATE example_table
- SET textfield = 'X'
- WHERE textfield = 'Y'
- and do_not_touch !=1
- ```
- The second way is sometimes way faster, even though it takes much longer to write out.
- Why would the second way be faster?
#3: Post edited
- I have two tables with millions of records. Every so often I need to join them and exclude just a handful of records where a bit(1) column is set to 1 instead of 0.
- I can do it with either,
```- WHERE is_excluded !=1
- ```
- or
```- WHERE example_table.pk NOT IN
- (
- SELECT pk FROM(
- SELECT pk FROM
- example_table
- WHERE is_excluded =1)
- AS t)
- ```
- The second way is sometimes way faster, even though it takes much longer to write out.
- Why would the second way be faster?
- I have two tables with millions of records. Every so often I need to join them and exclude just a handful of records where a bit(1) column is set to 1 instead of 0.
- I can do it with either,
- ```sql
- WHERE is_excluded !=1
- ```
- or
- ```sql
- WHERE example_table.pk NOT IN
- (
- SELECT pk FROM(
- SELECT pk FROM
- example_table
- WHERE is_excluded =1)
- AS t)
- ```
- The second way is sometimes way faster, even though it takes much longer to write out.
- Why would the second way be faster?
#2: Post edited
I have two tables with millions of records. Every so often I need to join them and exclude just handful of records where a bit(1) column is set to 1 instead of 0.- I can do it with either,
- ```
- WHERE is_excluded !=1
- ```
- or
- ```
- WHERE example_table.pk NOT IN
- (
- SELECT pk FROM(
- SELECT pk FROM
- example_table
- WHERE is_excluded =1)
- AS t)
- ```
- The second way is sometimes way faster, even though it takes much longer to write out.
- Why would the second way be faster?
- I have two tables with millions of records. Every so often I need to join them and exclude just a handful of records where a bit(1) column is set to 1 instead of 0.
- I can do it with either,
- ```
- WHERE is_excluded !=1
- ```
- or
- ```
- WHERE example_table.pk NOT IN
- (
- SELECT pk FROM(
- SELECT pk FROM
- example_table
- WHERE is_excluded =1)
- AS t)
- ```
- The second way is sometimes way faster, even though it takes much longer to write out.
- Why would the second way be faster?
#1: Initial revision
Why would excluding records by creating a temporary table of their primary keys be faster than simply excluding by value?
I have two tables with millions of records. Every so often I need to join them and exclude just handful of records where a bit(1) column is set to 1 instead of 0. I can do it with either, ``` WHERE is_excluded !=1 ``` or ``` WHERE example_table.pk NOT IN ( SELECT pk FROM( SELECT pk FROM example_table WHERE is_excluded =1) AS t) ``` The second way is sometimes way faster, even though it takes much longer to write out. Why would the second way be faster?