REGEXP_COUNT (Transact-SQL) preview

2025-05-22

Applies to: SQL Server 2025 (17.x) Preview Azure SQL Database Azure SQL Managed Instance SQL database in Microsoft Fabric

Note

As a preview feature, the technology presented in this article is subject to Supplemental Terms of Use for Microsoft Azure Previews.

Counts the number of times that a regular expression pattern is matched in a string.

REGEXP_COUNT (
    string_expression,
    pattern_expression [ , start [ , flags ] ]
)

Arguments

string_expression

An expression of a character string.

Can be a constant, variable, or column of character string.

Data types: char, nchar, varchar, or nvarchar.

Note

The REGEXP_LIKE, REGEXP_COUNT, and REGEXP_INSTR functions support LOB types (varchar(max) and nvarchar(max)) up to 2 MB for the string_expression parameter.

pattern_expression

Regular expression pattern to match. Usually a text literal.

Data types: char, nchar, varchar, or nvarchar. pattern_expression supports a maximum character length of 8,000 bytes.

start

Specify the starting position for the search within the search string. Optional. Type is int or bigint.

The numbering is 1-based, meaning the first character in the expression is 1 and the value must be >= 1. If the start expression is less than 1, the returned pattern_expression begins at the first character that is specified in string_expression. If the start expression is greater than the length of string_expression, the function returns 0. The default is 1.

If the start expression is less than 1, the query returns an error.

flags

One or more characters that specify the modifiers used for searching for matches. Type is varchar or char, with a maximum of 30 characters.

For example, ims. The default is c. If an empty string (' ') is provided, it will be treated as the default value ('c'). Supply c or any other character expressions. If flag contains multiple contradictory characters, then SQL Server uses the last character.

For example, if you specify ic the regex returns case-sensitive matching.

If the value contains a character other than those listed at Supported flag values, the query returns an error like the following example:

Invalid flag provided. '<invalid character>' are not valid flags. Only {c,i,s,m} flags are valid.

Supported flag values

Flag	Description
`i`	Case-insensitive (default `false`)
`m`	Multi-line mode: `^` and `$` match begin/end line in addition to begin/end text (default `false`)
`s`	Let `.` match `\n` (default `false`)
`c`	Case-sensitive (default `true`)

Return value

int

Examples

Count how many times the letter a appears in each product name.

SELECT PRODUCT_NAME,
       REGEXP_COUNT(PRODUCT_NAME, 'a') AS A_COUNT
FROM PRODUCTS;

Count how many products have a name that ends with ing.

SELECT COUNT(*)
FROM PRODUCTS
WHERE REGEXP_COUNT(PRODUCT_NAME, 'ing$') > 0;

Count how many products have a name that contains three consecutive consonants, ignoring case.

SELECT COUNT(*)
FROM PRODUCTS
WHERE REGEXP_COUNT(PRODUCT_NAME, '[^aeiou]{3}', 1, 'i') > 0;

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