LIKE Patterns

Percent Suffix

A leading percent sign allows earlier text.

highlighted = computed this step

Percent wildcard at the start

A percent sign at the start can cover earlier characters.

percent then suffix\text{percent then suffix}

Read suffix matches

The pattern keeps 2 rows that end with a.

TRUE rows=2\text{TRUE rows}=2

LIKE-pattern examples are tiny finite WHERE-style filters with a small SQL-like pattern subset; collations, escapes, dialect behavior, indexes, optimizer behavior, and product claims are out of scope.

Percent wildcard at the start: base rowsidname1Ada2Al3Alan4Bea5Jo6NULL LIKE evaluationsourcevaluepatterntruthkept0Ada%aTRUEyes1Al%aFALSEno2Alan%aFALSEno3Bea%aTRUEyes4Jo%aFALSEno5NULL%aUNKNOWNno LIKE output rowsidname1Ada4Bea LIKE factsfactvalueinputRowCount6outputRowCount2trueRows2falseRows3unknownRows1patternKindpercentrowOrdersource_order

Required ending

The ending letter still has to match after the wildcard part.

required suffix\text{required suffix}

Summary

Percent can hide the beginning, but the suffix remains exact.

suffix check\text{suffix check}