Select Rows Where Value from One Column Matches Other Column
TL;DR: Use a JOIN. I’ve got a table representing a tree, using two columns:
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CREATE TABLE "EXAMPLE" ( "PROP_ID" VARCHAR2(20 BYTE) NOT NULL ENABLE, "PARENT_PROP_ID" VARCHAR2(20 BYTE) NOT NULL ENABLE, /* * Data ... */ "CLASS_ID" VARCHAR2(20 BYTE) NOT NULL ENABLE ) |
and I want to select all children for parents whose CLASS_ID have a certain value (e.g. abcd). The way I could do it was via a JOIN statement:
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SELECT * FROM EXAMPLE child JOIN EXAMPLE parent on (child.parent_prop_id = parent.prop_id) WHERE parent.class_id = 'abcd'; |
This will: Perform a join where child.parent_prop_id = parent.prop_id Filter only parent.class_id = ‘abcd’ Simple. Bonus This will work with other databases as well :) HTH, A little experiment: If you find this post and ad below useful, please check the ad out :-)
