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Included use of underscore wildcard character (#22613)

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* Included use of underscore wildcard character 

Included the use and example of wildcard character underscore which can be used with LIKE operator

* fix(guide): minor typos and grammar
This commit is contained in:
Shad Ahmad Zaidi
2018-11-24 18:00:34 +05:30
committed by nik
parent 4f1677a9c6
commit 6df0cb92fb
1 changed files with 24 additions and 1 deletions
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25
guide/english/sql/sql-like-operator/index.md
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@ -4,7 +4,7 @@ title: SQL LIKE Operator
## SQL LIKE Operator
### LIKE Operator defined
The `LIKE` operator is used in a `WHERE` or `HAVING` (as part of the `GROUP BY`) to limit the selected rows to the items when a column has a certain pattern of characters contained in it.
The `LIKE` operator is used in a `WHERE` or `HAVING` (as part of the `GROUP BY`) to limit the selected rows to the items when a column has a certain pattern of characters contained in it. It is used along with two wildcard characters namely underscore **_** and percent **%** symbol
### ILIKE Opeartor
The 'ILIKE' works same as 'LIKE' but it ignores case-sensitivity in the string. The provided pattern string should be the case-sensitive else you will get an error. To avoid these errors, just write `ILIKE` instead of `LIKE`.
@ -18,9 +18,11 @@ FullName ILIKE 'monique%' // --you will not see any error now.
* Determining if a string starts or ends with a given string pattern
* Determining if a pattern exists in the middle of the string
* Determining if a string is not contained in the string
* Determining if a string is has specified letter at any position in the string
### A column starts or ends with a given string pattern
This SQL will select students that have `FullName` starting with "Monique" or ending with "Greene".
Here **%** means that it can be replaced by any number of characters.
```sql
SELECT studentID, FullName, sat_score, rcd_updated
@ -80,6 +82,27 @@ WHERE FullName NOT LIKE '%cer Pau%' AND FullName NOT LIKE '%"Ted"%';
7 rows in set (0.00 sec)
```
### A string has a specific letter say o in the second position
This SQL shows records having **o** as the alphabet in second position in the FullName column.
Here **_** means that it can be replaced by only a single character.
```sql
SELECT studentID, FullName, sat_score, rcd_updated
FROM student
WHERE FullName LIKE '_o%';
```
```text
+-----------+----------------------+-----------+---------------------+
| studentID | FullName | sat_score | rcd_updated |
+-----------+----------------------+-----------+---------------------+
| 1 | Monique Davis | 400 | 2017-08-16 15:34:50 |
| 4 | Louis Ramsey | 1200 | 2017-08-16 15:34:50 |
| 6 | Sophie Freeman | 1200 | 2017-08-16 15:34:50 |
| 8 | Donald D. Chamberlin | 2400 | 2017-08-16 15:35:33 |
+-----------+----------------------+-----------+---------------------+
4 rows in set (0.00 sec)
```
*Here is the current full student list to compare to the where clause result sets above.*
```sql