Answer
COUNT(*) counts all rows including NULLs, while COUNT(column) counts only non-null values.
Quick Answer
COUNT(*): counts all rows in the result set including NULLs (counts the row, not a column value). COUNT(column): counts rows where the specified column is NOT NULL - skips NULL values. COUNT(DISTINCT col): counts unique non-NULL values. Example: if 10 rows, 2 have NULL email - COUNT(*) returns 10, COUNT(email) returns 8. Use COUNT(*) for total rows, COUNT(col) for non-null counts.
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SugharaIQ Editorial Team
Verified Answer
This answer has been peer-reviewed by industry experts holding senior engineering roles to ensure technical accuracy and relevance for modern interview standards.
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Source: SugharaIQ