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Escape LIKE wildcard chars correctly in SQL Server StartsWith(char) #39076

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AndriySvyryd merged 2 commits into from
Oct 2, 2026
Merged

Escape LIKE wildcard chars correctly in SQL Server StartsWith(char) #39076

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99a4dd8
Escape LIKE wildcard chars correctly in SQL Server StartsWith(char)
ilkertskn Sep 23, 2026
838bb57
Use interpolation for all LIKE patterns and skip ESCAPE for char wild…
ilkertskn Sep 26, 2026
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51 changes: 30 additions & 21 deletions src/EFCore.SqlServer/Query/Internal/SqlServerSqlTranslatingExpressionVisitor.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -535,8 +535,8 @@ Expression TranslateStartsEndsWithContains(Expression instance, Expression patte
_sqlExpressionFactory.Constant(
methodType switch
{
StartsEndsWithContains.StartsWith => s + '%',
StartsEndsWithContains.EndsWith => '%' + s,
StartsEndsWithContains.StartsWith => $"{s}%",
StartsEndsWithContains.EndsWith => $"%{s}",
StartsEndsWithContains.Contains => $"%{s}%",

_ => throw new ArgumentOutOfRangeException(nameof(methodType), methodType, null)
Expand All @@ -552,8 +552,8 @@ string when _sqlServerSingletonOptions.EngineType is SqlServerEngineType.AzureSy
_sqlExpressionFactory.Constant(
methodType switch
{
StartsEndsWithContains.StartsWith => EscapeLikePattern(s) + '%',
StartsEndsWithContains.EndsWith => '%' + EscapeLikePattern(s),
StartsEndsWithContains.StartsWith => $"{EscapeLikePattern(s)}%",
StartsEndsWithContains.EndsWith => $"%{EscapeLikePattern(s)}",
StartsEndsWithContains.Contains => $"%{EscapeLikePattern(s)}%",

_ => throw new ArgumentOutOfRangeException(nameof(methodType), methodType, null)
Expand All @@ -566,20 +566,27 @@ string when _sqlServerSingletonOptions.EngineType is SqlServerEngineType.AzureSy
_sqlExpressionFactory.Constant(
methodType switch
{
StartsEndsWithContains.StartsWith => s + "%",
StartsEndsWithContains.EndsWith => "%" + s,
StartsEndsWithContains.StartsWith => $"{s}%",
StartsEndsWithContains.EndsWith => $"%{s}",
StartsEndsWithContains.Contains => $"%{s}%",

_ => throw new ArgumentOutOfRangeException(nameof(methodType), methodType, null)
})),

// Azure Synapse does not support ESCAPE clause in LIKE
// fallback to translation like with column/expression
char s when _sqlServerSingletonOptions.EngineType is SqlServerEngineType.AzureSynapse
=> TranslateWithoutLike(
patternIsNonEmptyConstantString: true,
pattern: _sqlExpressionFactory.Constant(s.ToString(), stringTypeMapping)),

char s => _sqlExpressionFactory.Like(
translatedInstance,
_sqlExpressionFactory.Constant(
methodType switch
{
StartsEndsWithContains.StartsWith => LikeEscapeChar + s + "%",
StartsEndsWithContains.EndsWith => "%" + LikeEscapeChar + s,
StartsEndsWithContains.StartsWith => $"{LikeEscapeChar}{s}%",
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StartsEndsWithContains.EndsWith => $"%{LikeEscapeChar}{s}",
StartsEndsWithContains.Contains => $"%{LikeEscapeChar}{s}%",

_ => throw new ArgumentOutOfRangeException(nameof(methodType), methodType, null)
Expand Down Expand Up @@ -621,8 +628,10 @@ string when _sqlServerSingletonOptions.EngineType is SqlServerEngineType.AzureSy
return TranslateWithoutLike();
}

SqlExpression TranslateWithoutLike(bool patternIsNonEmptyConstantString = false)
SqlExpression TranslateWithoutLike(bool patternIsNonEmptyConstantString = false, SqlExpression? pattern = null)
{
pattern ??= translatedPattern;

return methodType switch
{
// For StartsWith/EndsWith, use LEFT or RIGHT instead to extract substring and compare:
Expand All @@ -634,15 +643,15 @@ StartsEndsWithContains.StartsWith or StartsEndsWithContains.EndsWith
=> _sqlExpressionFactory.AndAlso(
_sqlExpressionFactory.IsNotNull(translatedInstance),
_sqlExpressionFactory.AndAlso(
_sqlExpressionFactory.IsNotNull(translatedPattern),
_sqlExpressionFactory.IsNotNull(pattern),
_sqlExpressionFactory.Equal(
_sqlExpressionFactory.Function(
methodType is StartsEndsWithContains.StartsWith ? "LEFT" : "RIGHT",
[
translatedInstance,
_sqlExpressionFactory.Function(
"LEN",
[translatedPattern],
[pattern],
nullable: true,
argumentsPropagateNullability: Statics.TrueArrays[1],
typeof(int))
Expand All @@ -651,7 +660,7 @@ StartsEndsWithContains.StartsWith or StartsEndsWithContains.EndsWith
argumentsPropagateNullability: Statics.TrueArrays[2],
typeof(string),
stringTypeMapping),
translatedPattern))),
pattern))),

// For Contains, just use CHARINDEX and check if the result is greater than 0.
StartsEndsWithContains.Contains when patternIsNonEmptyConstantString
Expand All @@ -665,11 +674,11 @@ StartsEndsWithContains.Contains when patternIsNonEmptyConstantString
=> _sqlExpressionFactory.AndAlso(
_sqlExpressionFactory.IsNotNull(translatedInstance),
_sqlExpressionFactory.AndAlso(
_sqlExpressionFactory.IsNotNull(translatedPattern),
_sqlExpressionFactory.IsNotNull(pattern),
_sqlExpressionFactory.OrElse(
CharIndexGreaterThanZero(),
_sqlExpressionFactory.Like(
translatedPattern,
pattern,
_sqlExpressionFactory.Constant(string.Empty, stringTypeMapping))))),

_ => throw new UnreachableException()
Expand All @@ -679,7 +688,7 @@ SqlExpression CharIndexGreaterThanZero()
=> _sqlExpressionFactory.GreaterThan(
_sqlExpressionFactory.Function(
"CHARINDEX",
[translatedPattern, translatedInstance],
[pattern, translatedInstance],
nullable: true,
argumentsPropagateNullability: Statics.TrueArrays[2],
typeof(int)),
Expand Down Expand Up @@ -746,24 +755,24 @@ SqlParameterExpression CreateRuntimeParameter(

string s => methodType switch
{
StartsEndsWithContains.StartsWith => EscapeLikePattern(s) + '%',
StartsEndsWithContains.EndsWith => '%' + EscapeLikePattern(s),
StartsEndsWithContains.StartsWith => $"{EscapeLikePattern(s)}%",
StartsEndsWithContains.EndsWith => $"%{EscapeLikePattern(s)}",
StartsEndsWithContains.Contains => $"%{EscapeLikePattern(s)}%",
_ => throw new ArgumentOutOfRangeException(nameof(methodType), methodType, null)
},

char s when !IsLikeWildChar(s) => methodType switch
{
StartsEndsWithContains.StartsWith => s + "%",
StartsEndsWithContains.EndsWith => "%" + s,
StartsEndsWithContains.StartsWith => $"{s}%",
StartsEndsWithContains.EndsWith => $"%{s}",
StartsEndsWithContains.Contains => $"%{s}%",
_ => throw new ArgumentOutOfRangeException(nameof(methodType), methodType, null)
},

char s => methodType switch
{
StartsEndsWithContains.StartsWith => LikeEscapeChar + s + "%",
StartsEndsWithContains.EndsWith => "%" + LikeEscapeChar + s,
StartsEndsWithContains.StartsWith => $"{LikeEscapeChar}{s}%",
StartsEndsWithContains.EndsWith => $"%{LikeEscapeChar}{s}",
StartsEndsWithContains.Contains => $"%{LikeEscapeChar}{s}%",
_ => throw new ArgumentOutOfRangeException(nameof(methodType), methodType, null)
},
Expand Down
14 changes: 7 additions & 7 deletions src/EFCore.Sqlite.Core/Query/Internal/SqliteSqlTranslatingExpressionVisitor.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -305,20 +305,20 @@ Expression TranslateStartsEndsWith(Expression instance, Expression pattern, bool
string s => s.Any(IsLikeWildChar)
? _sqlExpressionFactory.Like(
translatedInstance,
_sqlExpressionFactory.Constant(startsWith ? EscapeLikePattern(s) + '%' : '%' + EscapeLikePattern(s)),
_sqlExpressionFactory.Constant(startsWith ? $"{EscapeLikePattern(s)}%" : $"%{EscapeLikePattern(s)}"),
_sqlExpressionFactory.Constant(LikeEscapeString))
: _sqlExpressionFactory.Like(
translatedInstance,
_sqlExpressionFactory.Constant(startsWith ? s + '%' : '%' + s)),
_sqlExpressionFactory.Constant(startsWith ? $"{s}%" : $"%{s}")),

char s => IsLikeWildChar(s)
? _sqlExpressionFactory.Like(
translatedInstance,
_sqlExpressionFactory.Constant(startsWith ? LikeEscapeString + s + "%" : '%' + LikeEscapeString + s),
_sqlExpressionFactory.Constant(startsWith ? $"{LikeEscapeChar}{s}%" : $"%{LikeEscapeChar}{s}"),
_sqlExpressionFactory.Constant(LikeEscapeString))
: _sqlExpressionFactory.Like(
translatedInstance,
_sqlExpressionFactory.Constant(startsWith ? s + "%" : "%" + s)),
_sqlExpressionFactory.Constant(startsWith ? $"{s}%" : $"%{s}")),

_ => throw new UnreachableException()
};
Expand Down Expand Up @@ -436,11 +436,11 @@ Expression TranslateStartsEndsWith(Expression instance, Expression pattern, bool
// Return % which always matches instead.
"" => "%",

string s => startsWith ? EscapeLikePattern(s) + '%' : '%' + EscapeLikePattern(s),
string s => startsWith ? $"{EscapeLikePattern(s)}%" : $"%{EscapeLikePattern(s)}",

char s when IsLikeWildChar(s) => startsWith ? LikeEscapeString + s + '%' : '%' + LikeEscapeString + s,
char s when IsLikeWildChar(s) => startsWith ? $"{LikeEscapeChar}{s}%" : $"%{LikeEscapeChar}{s}",

char s => startsWith ? s + "%" : "%" + s,
char s => startsWith ? $"{s}%" : $"%{s}",

_ => throw new UnreachableException()
};
Expand Down
63 changes: 63 additions & 0 deletions test/EFCore.Specification.Tests/Query/FunkyDataQueryTestBase.cs
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Expand Up @@ -242,6 +242,69 @@ await AssertQuery(
ss => ss.Set<FunkyCustomer>().Where(c => true).Select(c => c.FirstName));
}

[Theory, MemberData(nameof(IsAsyncData))]
public virtual async Task String_starts_with_on_argument_with_wildcard_char_constant(bool async)
{
await AssertQuery(
async,
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ss => ss.Set<FunkyCustomer>().Where(c => c.FirstName!.StartsWith('%')).Select(c => c.FirstName),
ss => ss.Set<FunkyCustomer>().Where(c => c.FirstName!.MaybeScalar(x => x.StartsWith('%')) == true).Select(c => c.FirstName));

await AssertQuery(
async,
ss => ss.Set<FunkyCustomer>().Where(c => c.FirstName!.StartsWith('_')).Select(c => c.FirstName),
ss => ss.Set<FunkyCustomer>().Where(c => c.FirstName!.MaybeScalar(x => x.StartsWith('_')) == true).Select(c => c.FirstName));

await AssertQuery(
async,
ss => ss.Set<FunkyCustomer>().Where(c => c.FirstName!.StartsWith('[')).Select(c => c.FirstName),
ss => ss.Set<FunkyCustomer>().Where(c => c.FirstName!.MaybeScalar(x => x.StartsWith('[')) == true).Select(c => c.FirstName));

await AssertQuery(
async,
ss => ss.Set<FunkyCustomer>().Where(c => c.FirstName!.StartsWith('B')).Select(c => c.FirstName),
ss => ss.Set<FunkyCustomer>().Where(c => c.FirstName!.MaybeScalar(x => x.StartsWith('B')) == true).Select(c => c.FirstName));

await AssertQuery(
async,
ss => ss.Set<FunkyCustomer>().Where(c => !c.FirstName!.StartsWith('_')).Select(c => c.FirstName),
ss => ss.Set<FunkyCustomer>().Where(c => c.FirstName!.MaybeScalar(x => x.StartsWith('_')) != true).Select(c => c.FirstName));
}

[Theory, MemberData(nameof(IsAsyncData))]
public virtual async Task String_starts_with_on_argument_with_wildcard_char_parameter(bool async)
{
var prm1 = '%';
await AssertQuery(
async,
ss => ss.Set<FunkyCustomer>().Where(c => c.FirstName!.StartsWith(prm1)).Select(c => c.FirstName),
ss => ss.Set<FunkyCustomer>().Where(c => c.FirstName!.MaybeScalar(x => x.StartsWith(prm1)) == true).Select(c => c.FirstName));

var prm2 = '_';
await AssertQuery(
async,
ss => ss.Set<FunkyCustomer>().Where(c => c.FirstName!.StartsWith(prm2)).Select(c => c.FirstName),
ss => ss.Set<FunkyCustomer>().Where(c => c.FirstName!.MaybeScalar(x => x.StartsWith(prm2)) == true).Select(c => c.FirstName));

var prm3 = '[';
await AssertQuery(
async,
ss => ss.Set<FunkyCustomer>().Where(c => c.FirstName!.StartsWith(prm3)).Select(c => c.FirstName),
ss => ss.Set<FunkyCustomer>().Where(c => c.FirstName!.MaybeScalar(x => x.StartsWith(prm3)) == true).Select(c => c.FirstName));

var prm4 = 'B';
await AssertQuery(
async,
ss => ss.Set<FunkyCustomer>().Where(c => c.FirstName!.StartsWith(prm4)).Select(c => c.FirstName),
ss => ss.Set<FunkyCustomer>().Where(c => c.FirstName!.MaybeScalar(x => x.StartsWith(prm4)) == true).Select(c => c.FirstName));

var prm5 = '_';
await AssertQuery(
async,
ss => ss.Set<FunkyCustomer>().Where(c => !c.FirstName!.StartsWith(prm5)).Select(c => c.FirstName),
ss => ss.Set<FunkyCustomer>().Where(c => c.FirstName!.MaybeScalar(x => x.StartsWith(prm5)) != true).Select(c => c.FirstName));
}

[Theory, MemberData(nameof(IsAsyncData))]
public virtual async Task String_starts_with_on_argument_with_bracket(bool async)
{
Expand Down
82 changes: 82 additions & 0 deletions test/EFCore.SqlServer.FunctionalTests/Query/FunkyDataQueryAzureSynapseTest.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -273,6 +273,88 @@ FROM [FunkyCustomers] AS [f]
""");
}

public override async Task String_starts_with_on_argument_with_wildcard_char_constant(bool async)
{
await base.String_starts_with_on_argument_with_wildcard_char_constant(async);

AssertSql(
"""
SELECT [f].[FirstName]
FROM [FunkyCustomers] AS [f]
WHERE [f].[FirstName] IS NOT NULL AND LEFT([f].[FirstName], LEN(N'%')) = N'%'
""",
//
"""
SELECT [f].[FirstName]
FROM [FunkyCustomers] AS [f]
WHERE [f].[FirstName] IS NOT NULL AND LEFT([f].[FirstName], LEN(N'_')) = N'_'
""",
//
"""
SELECT [f].[FirstName]
FROM [FunkyCustomers] AS [f]
WHERE [f].[FirstName] IS NOT NULL AND LEFT([f].[FirstName], LEN(N'[')) = N'['
""",
//
"""
SELECT [f].[FirstName]
FROM [FunkyCustomers] AS [f]
WHERE [f].[FirstName] LIKE N'B%'
""",
//
"""
SELECT [f].[FirstName]
FROM [FunkyCustomers] AS [f]
WHERE [f].[FirstName] IS NULL OR LEFT([f].[FirstName], LEN(N'_')) <> N'_'
""");
}

public override async Task String_starts_with_on_argument_with_wildcard_char_parameter(bool async)
{
await base.String_starts_with_on_argument_with_wildcard_char_parameter(async);

AssertSql(
"""
@prm1='%' (Size = -1) (DbType = String)

SELECT [f].[FirstName]
FROM [FunkyCustomers] AS [f]
WHERE [f].[FirstName] IS NOT NULL AND LEFT([f].[FirstName], LEN(@prm1)) = @prm1
""",
//
"""
@prm2='_' (Size = -1) (DbType = String)

SELECT [f].[FirstName]
FROM [FunkyCustomers] AS [f]
WHERE [f].[FirstName] IS NOT NULL AND LEFT([f].[FirstName], LEN(@prm2)) = @prm2
""",
//
"""
@prm3='[' (Size = -1) (DbType = String)

SELECT [f].[FirstName]
FROM [FunkyCustomers] AS [f]
WHERE [f].[FirstName] IS NOT NULL AND LEFT([f].[FirstName], LEN(@prm3)) = @prm3
""",
//
"""
@prm4='B' (Size = -1) (DbType = String)

SELECT [f].[FirstName]
FROM [FunkyCustomers] AS [f]
WHERE [f].[FirstName] IS NOT NULL AND LEFT([f].[FirstName], LEN(@prm4)) = @prm4
""",
//
"""
@prm5='_' (Size = -1) (DbType = String)

SELECT [f].[FirstName]
FROM [FunkyCustomers] AS [f]
WHERE [f].[FirstName] IS NULL OR LEFT([f].[FirstName], LEN(@prm5)) <> @prm5
""");
}

public override async Task String_starts_with_on_argument_with_bracket(bool async)
{
await base.String_starts_with_on_argument_with_bracket(async);
Expand Down
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