The ILIKE keyword is used in a WHERE clause to search for a specified pattern in a. The IN Condition The IN condition lets you set a list of values that must match values in your tables. (underscore) matches any single character. (percent) matches any string with zero or more characters. LIKE uses wildcards, which are used to query similar values, but IN and NOT return precise record sets based on specific values. SELECT column-names FROM table-name WHERE column-name LIKE value Wildcard characters allowed in value are (percent) and (underscore). PostgreSQL also supports a null-safe equality operator: SELECT * FROM table WHERE some_text IS DISTINCT FROM 'anything' īut unfortunately, this works only for equality, not for LIKE/ILIKE with patterns and wildcards. The PostgreSQL NOT ILIKE keyword is the negation of ILIKE keyword. Some SQL keywords that help you build complex statements include IN, NOT, and LIKE. Or: SELECT * FROM table WHERE COALESCE(some_text, '') NOT ILIKE '%anything%' All the wildcards can also be used in combinations Here are some examples showing different LIKE operators with '' and '' wildcards: LIKE Operator. The following differences pertain to LIKE and its variants: LIKE operates on UTF-8 character strings. Vertica also supports several non-standard variants, notably ILIKE, which is equivalent to LIKE except it performs case-insensitive searches. So the solution for you is either always store a non-null string in your column, or else use an expression to account for tri-value logic: SELECT * FROM table WHERE some_text NOT ILIKE "%anything%' OR some_text IS NULL Represents any single character within the specified range. The LIKE predicate is compliant with the SQL standard. Those of us familiar with boolean algebra know that NOT TRUE is FALSE, and NOT FALSE is TRUE.īut the tricky part is that NOT UNKNOWN is still UNKNOWN. This often trips people up in SQL, because it's "tri-value logic." An expression can be TRUE, FALSE, or UNKNOWN. The ILIKE keyword is used in a WHERE clause to search for a specified pattern in a specified column. In other words, if I don't tell you my middle name, and you don't tell me your middle name, how can we know if our two middle names are the same name or different names? We can't know. The PostgreSQL NOT ILIKE keyword is the negation of ILIKE keyword.
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