This example creates a table containing several strings to demonstrate regular expressions. If you are porting a regular expression query from an Oracle database, remember that Oracle considers a zero-length string to be equivalent to NULL, while Vertica does not. This function operates on UTF-8 strings using the default locale, even if the locale has been set to something else. All spaces in the regular expression that you want to be matched in strings must be escaped with a backslash ( \) character. Comments start with a hash ( #) character and end with a newline ( \n). Using the x modifier causes the function to ignore all unescaped space characters and comments in the regular expression. operator matches any character except a newline.Īdd comments to your regular expressions. Without the m modifier, the start and end of line operators match only the start and end of the string.Īllow the single character regular expression operator (. Using this modifier, the start of line ( ^) and end of line ( $) regular expression operators match line breaks ( \n) within the string. Treat the string to match as multiple lines. Treat strings as binary octets, rather than UTF-8 characters.įorce the match to be case sensitive (the default). ![]() One or more single-character flags that modify how the regular expression finds matches in string: b ![]() See the Perl Regular Expressions Documentation for details. The syntax of the regular expression is compatible with the Perl 5 regular expression syntax. If string exists in a _raw_ column of a flex or columnar table, cast string to a LONG VARCHAR before searching for pattern.Ī string containing the regular expression to match against the string. The VARCHAR or LONG VARCHAR string to search for a regular expression pattern match. Syntax REGEXP_LIKE( string, pattern ) Parameters string This function is similar to the LIKE-predicate, except that it uses regular expressions rather than simple wildcard character matching. ON employee.ident = employee_mdata_history.Returns true if the string matches the regular expression. , row_number() over (partition by substring(employee_id,1,4) SELECT employee_id, employee_ident, utc_dt, rx_dt Marks Presbyterian Church in Altamonte Springs, Florida, is offered for sale by the propertys new owner. I believe SQL-server 2008 supports window functions like row_number(), so you can use something like: SELECT employee_id, employee_ident, utc_dt, rx_dt The 3-manual, 20-rank pipe organ installed in the former St. Since the legs in the union is guaranteed to be disjoint a UNION ALL can be used, and that might be a performance advantage compared to using just a UNION. ( SELECT top 1 employee_id, employee_ident, utc_dt, rx_dt One way to achieve this is to use a union: SELECT t1.* I guess you want 1 row where employee_id like 'emp1%' and another where employee_id like 'emp3%'. In addition I'll add a pattern search, but this solution returns all records that matches the pattern: LIKE 'emp%' If you need the TOP (X) rows WHERE employee_id LIKE 'emp1%' plus TOP (X) rows WHERE employee_id LIKE 'emp3%' you can use two select statements joined with UNION ALL. Keep in mind that you're using TOP 1, you'll get one row maximum, no matter how many conditions you use. I've set up an example: create table employees(employee_id varchar(10), employee_name varchar(100)) Have a look at OR (Transact-SQL) on MS-Docs. ON employee.ident = employee_mdata_history.employee_ident You should use an OR/AND condition: SELECT TOP (1) ![]() INNER JOIN dbo.employee_mdata_history AS h You can always use short aliases to avoid repeating potentially long table names. That makes your query easier to read/understand. to every pattern, limiting the number of rows for each pattern to the corresponding value from the pattern list.Īs a side note, please let me take this opportunity to suggest that you always qualify your columns with the table alias in a query that is reading from two or more tables. The CROSS APPLY operator applies your query to every row of the pattern list, i.e. The VALUES row constructor represents your pattern list as a table, additionally supplying each pattern with the number of rows to retrieve for that pattern. ON employee.ident=employee_mdata_history.employee_ident Alternatively you can try the following method: SELECTĮmployee_id, employee_ident, utc_dt, rx_dt
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