Joining _Open Directly to _Click Can Explode Rows
A subscriber/job report returns far more rows than either source and aggregates start looking absurd.
Trust & provenancePRODUCTION
Evidence tierPRODUCTIONOfficial sources0Other sources0Last verifiedNot recorded
Evidence tier describes my hands-on relationship with the content. Official sources describe platform contracts/documentation. Production observations should not automatically be treated as official limits.
Both event views can contain multiple rows at the same subscriber/job grain. Joining raw events together creates many-to-many multiplication.
What to check
- What is the grain of _Open input?
- What is the grain of _Click input?
- Are you joining events before reducing to one row per reporting key?
Make it cheaper next time
- Pre-aggregate each event source separately, then join the reduced sets.
- State output grain at the top of every reporting query.
sqlopenclickgrain