Applies to:  CELONIS 4.0 CELONIS 4.2 CELONIS 4.3 CELONIS 4.4 CELONIS 4.5 CELONIS 4.6 CELONIS 4.7 

Description

The LIKE predicate determines whether the right expression string matches the left expression string. The output can be negated by using NOT LIKE.

LIKE can only be applied to STRING values.

[NOT] LIKE can be used in the following contexts:

Syntax

table.column LIKE pattern
table.column NOT LIKE pattern

NULL handling

If any input expression is NULL, NULL is returned.

Wildcards

The following wildcards can be used in the right pattern expression:

  • %: Matches any string with zero or more characters.
  • _: Matches exactly one character.

Implicit Wildcards

If no wildcard character is present in the <pattern>, leading and trailing % wildcards are implicitly assumed: %<pattern>%. When wildcards are implicitly assumed, then comparison is not case sensitive.

Wildcard Escaping

Wildcards can be escaped with backslash for matching the literal wildcard characters in a STRING (\%, \_). For more details on escape sequences see the STRING data type.

Examples


[1] No wildcards are included. LIKE will assume leading and trailing '%' wildcards, which means that LIKE matches in all examples:

Query
Column1
CASE WHEN ( "Table1"."Haystack" LIKE "Table1"."Needle" ) THEN 'match' ELSE 'no match' END
Input
Table1
Haystack : STRINGNeedle : STRING
'abcde''a'
'abcde''bcd'
'abcde''abcde'
'abcde''e'
'aBcDE''e'
Output
Result
Column1 : STRING
'match'
'match'
'match'
'match'
'match'



[2] Wildcards are included. LIKE will not leading and trailing '%' wildcards, which means that LIKE does not match in all examples:

Query
Column1
CASE WHEN ( "Table1"."Haystack" LIKE "Table1"."Needle" ) THEN 'match' ELSE 'no match' END
Input
Table1
Haystack : STRINGNeedle : STRING
'abcde''a_'
'abcde''b_d'
'abcde''a%d'
'abcde''_e'
Output
Result
Column1 : STRING
'no match'
'no match'
'no match'
'no match'



[3] Wildcards are included. LIKE will not leading and trailing '%' wildcards, but in all examples, LIKE matches:

Query
Column1
CASE WHEN ( "Table1"."Haystack" LIKE "Table1"."Needle" ) THEN 'match' ELSE 'no match' END
Input
Table1
Haystack : STRINGNeedle : STRING
'abcde''a_c_e'
'abcde''_b_d_'
'abcde''a%d_'
'abcde''%e%'
Output
Result
Column1 : STRING
'match'
'match'
'match'
'match'



[4] If no wildcards are included, comparison is case insensitive. If wildcards are included, comparison is case sensitive:

Query
Column1
CASE WHEN ( "Table1"."Haystack" LIKE "Table1"."Needle" ) THEN 'match' ELSE 'no match' END
Input
Table1
Haystack : STRINGNeedle : STRING
'abcde''a'
'abcde''A'
'abcde''aBcDe'
'abcde''B'
'abcde''a_C_e'
'abcde''_B%'
'abcde''%e%'
'abcde''%E%'
'aBcDe''AbCdE'
Output
Result
Column1 : STRING
'match'
'match'
'match'
'match'
'no match'
'no match'
'match'
'no match'
'match'



[5] NOT LIKE: Results are negated. If no wildcards are included, comparison is case insensitive. If wildcards are included, comparison is case sensitive:

Query
Column1
CASE WHEN ( "Table1"."Haystack" NOT LIKE "Table1"."Needle" ) THEN 'match' ELSE 'no match' END
Input
Table1
Haystack : STRINGNeedle : STRING
'abcde''a'
'abcde''A'
'abcde''aBcDe'
'abcde''B'
'abcde''a_C_e'
'abcde''_B%'
'abcde''%e%'
'abcde''%E%'
'aBcDe''AbCdE'
Output
Result
Column1 : STRING
'no match'
'no match'
'no match'
'no match'
'match'
'match'
'no match'
'match'
'no match'



[6] If any side of the LIKE operator is NULL, NULL is returned:

Query
Column1
CASE WHEN ( "Table1"."Haystack" LIKE "Table1"."Needle" ) THEN 'match' ELSE 'no match' END
Input
Table1
Needle : STRINGHaystack : STRING
nullnull
null' '
null''
null' '
null' '
null'0'
null'%'
null'_'
'abc'null
Output
Result
Column1 : STRING
null
null
null
null
null
null
null
null
null



[7] Wildcards can be escaped with a backslash. In a STRING column no escaping of the backslash escape character itself is needed:

Query
Column1
CASE WHEN ( "Table1"."Haystack" LIKE "Table1"."Needle" ) THEN 'match' ELSE 'no match' END
Input
Table1
Haystack : STRINGNeedle : STRING
'_a''\_a'
'%a''\%a'
'ab''\_b'
'ab''\%b'
'a''\_'
'aba''\%'
Output
Result
Column1 : STRING
'match'
'match'
'no match'
'no match'
'no match'
'no match'



[8] There is an escaped wildcard in the <pattern>, so no implicit wildcards are added and comparison is case sensitive. Note that in STRING constants the backslash escape character itself must be escaped with another backslash:

Query
Column1
CASE
    WHEN
        "Table1"."Haystack" LIKE '\\_a'
    THEN
        'Input [' || "Table1"."Haystack" || '] matches pattern [\\\\_a]'
    WHEN
        "Table1"."Haystack" LIKE '%\\_a%'
    THEN
        'Input [' || "Table1"."Haystack" || '] matches pattern [%\\\\_a%]'
    ELSE
        'Input [' || "Table1"."Haystack" || '] has no match'
END
Input
Table1
Haystack : STRING
'a'
'a_'
'_a'
'_A'
'b_a'
'_ac'
'b_Ac'
Output
Result
Column1 : STRING
'Input [a] has no match'
'Input [a_] has no match'
'Input [_a] matches pattern [\\_a]'
'Input [_A] has no match'
'Input [b_a] matches pattern [%\\_a%]'
'Input [_ac] matches pattern [%\\_a%]'
'Input [b_Ac] has no match'



[9] The expression strings can also be string literals:

Query
Column1
CASE WHEN ( "Table1"."Haystack" LIKE 'a' ) THEN 'match' ELSE 'no match' END
Input
Table1
Haystack : STRING
'a'
'a a'
'aba'
' '
''
null
Output
Result
Column1 : STRING
'match'
'match'
'match'
'no match'
'no match'
null



[10] Use LIKE in a FILTER expression:

Query
Filter
FILTER "Table1"."Haystack" LIKE "Table1"."Needle";
Column1
"Table1"."Haystack"
Column2
"Table1"."Needle"
Input
Table1
Haystack : STRINGNeedle : STRING
'abcde''a'
'abcde''bcd'
'abcde''abcde'
'abcde''%e'
'abcde''E'
'abcde''%E'
'abcde''_b'
null'a'
'abcde'null
'%a''\%a'
'ab''\_b'
Output
Result
Column1 : STRINGColumn2 : STRING
'abcde''a'
'abcde''bcd'
'abcde''abcde'
'abcde''%e'
'abcde''E'
'%a''\%a'


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