regexp_count

The regexp_count function is a function in SQL that is used to count the number of occurrences of a specific pattern or regular expression in a string or text column. It is often used in combination with the regexp_replace function to identify and replace specific patterns in the data.
The syntax of the regexp_count function is as follows:
regexp_count(source_string, pattern, start_position, match_param)
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Here,

source_string is the string or column name that contains the text to be searched.
pattern is the regular expression or pattern to be matched.
start_position is an optional parameter that specifies the starting position within the source_string where the search should begin. If not specified, the search will start at the beginning of the string.
match_param is an optional parameter that specifies additional matching options to be used. This can be used to control the case sensitivity, matching mode, and other options.

For example, the following query counts the number of occurrences of the word "cat" in a column called "description" in a table called "animals":
SELECT regexp_count(description, 'cat') as cat_count
FROM animals;
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This will return a result set that includes a column called "cat_count" that contains the number of occurrences of the word "cat" in the "description" column for each row in the "animals" table.